WO2024194153A1

WO2024194153A1 - Rsv-f-encoding nucleic acids

Info

Publication number: WO2024194153A1
Application number: PCT/EP2024/056893
Authority: WO
Inventors: Nicholas John BARROWS; Marco BIANCUCCI; Corey Patrick Mallett; Emily PHUNG
Original assignee: GlaxoSmithKline Biologicals SA
Current assignee: GlaxoSmithKline Biologicals SA
Priority date: 2023-03-17
Filing date: 2024-03-15
Publication date: 2024-09-26
Anticipated expiration: 2025-09-17

Abstract

The present disclosure provides inter alia, a recombinant ribonucleic acid (RNA) encoding a respiratory syncytial virus fusion (RSV-F) protein comprising an F2 and an F1 domain; wherein the RSV-F protein further comprises, relative to a wild-type RSV-F sequence, the substitution of a residue for a C residue in both of the F2 and F1 domains.

Description

Docket No: 70330WO01 RSV-F-ENCODING NUCLEIC ACIDS FIELD The present disclosure is in the field of vaccinology, in particular antigen design for nucleic acid-based vaccines. BACKGROUND Respiratory syncytial virus (“RSV”) is a ribonucleic acid virus of the Pneumoviridae family of which two antigenically distinct subgroups, referred to as RSV A and RSV B, exist. RSV is a leading cause of infant and older adult hospitalisation and mortality. Each year in the United States, RSV leads to approximately 58,000 hospitalisations with 100-500 deaths among children under five [1], and 177,000 hospitalisations with 14,000 deaths among adults aged 65 years and above [2]. The development of a safe and efficacious vaccine to prevent severe disease and hospitalization from RSV is therefore a high priority. The antiviral drug ribavirin is the only approved antiviral therapy for RSV treatment, but its use is restricted to severe hospitalized cases in infants and young children [3]. Furthermore, two RSV- specific humanized monoclonal antibodies, palivizumab (Synagis) and motavizumab, are confirmed to be safe and effective in reducing RSV hospitalization rates and serious complications among high-risk children in multiple clinical settings [4, 5, 6, 7, 8]. Available treatment for RSV in older adults is generally supportive in nature, consisting of supplemental oxygen, intravenous fluids and bronchodilators. However, there evidently remains a need for safe and effective prophylactic vaccines against RSV. The RSV fusion (“RSV-F”) protein in the viral envelope is the most effective target of neutralizing antibodies, such as motavizumab. Recent advances in RSV-F structural biology have revealed changes in its antigenic characteristics that occur during the fusion process between the viral envelope and host cell membrane. RSV-F adopts a metastable “pre-fusion” conformation in the viral envelope as a homotrimer, and then an irreversible and distinct “post-fusion” conformation during fusion with the host cell membrane (see Figure 2 of [9]). The trimeric pre-fusion conformation is more immunogenic, and is bound by most RSV-F-specific neutralising antibodies in human sera. To date, there remains a need for pre-fusion RSV-F antigens, which, when encoded into nucleic acid- based vaccines, elicit effective neutralising immune responses against RSV. Docket No: 70330WO01 SUMMARY The inventors have found that a ribonucleic acid (RNA)-based vaccine expressing an engineered RSV- F protein elicits potent neutralising antibody responses against RSV in vivo. The engineered RSV-F protein comprises mutations relative to wild-type RSV-F, such as the introduction of cysteine residues into the F2 and F1 domains of the protein, which form a disulphide bond when expressed. As detailed in e.g. in Example 2, the expressed protein elicits a potent neutralising antibody response against e.g. RSV of the A subtype (see construct F(i); see e.g. Figure 3). Said neutralising antibody response is likely to inhibit viral replication in the lungs and other respiratory sites, leading to protective efficacy in a subject. Without wishing to be bound by theory, the engineered RSV-F protein may consistently retain the immunogenic pre-fusion conformation over time when expressed on the cell surface. Hence, the subject’s immune system may be exposed to pre- fusion RSV-F over longer periods in comparison to other RSV-F proteins (in which the pre-fusion conformation is less stable), thereby leading to the observed neutralising antibody responses. As detailed in e.g. Example 2, surprisingly, construct F(i) elicited an overall more potent neutralising antibody response in vivo than control constructs such as F(iii), in spite of F(iii) demonstrating greater in vitro expression levels (see e.g. Figure 1 for in vitro data; Figure 3 for in vivo data). Similar in vivo results were observed in e.g. Example 4, and furthermore construct F(i) elicited more potent cross- neutralising antibody responses (against both RSV-A subtype strains and RSV-B subtype strains) than control constructs (see e.g. Figure 4B). Currently, protein subunit-based RSV vaccines are being pursued, for at least the older adult population [10]. However, there are potential advantages to nucleic acid-based vaccines, such as avoiding the risks of pre- to post-fusion conformational change of a protein subunit during storage and transportation. The RNA provided herein may thus expand patient options to include additional nucleic acid-based vaccines. Therefore, the RNA generated by the inventors (and proteins encoded thereby) may be useful, in particular in prophylactic vaccination against RSV. Accordingly, in a first independent aspect, the present disclosure provides a recombinant RNA encoding an RSV-F protein comprising an F2 and an F1 domain; wherein the RSV-F protein further comprises, relative to a wild-type RSV-F sequence, the substitution of a residue for a C residue in both of the F2 and F1 domains. In a further independent aspect, the present disclosure provides an RSV-F protein that is encoded by a nucleic acid of the present disclosure. Docket No: 70330WO01 In a further independent aspect, the present disclosure provides a host cell comprising an RNA of the present disclosure. In a further independent aspect, the present disclosure provides a carrier (preferably, a lipid nanoparticle) comprising an RNA of the present disclosure. In a further independent aspect, the present disclosure provides a pharmaceutical composition comprising an RNA, or carrier (preferably lipid nanoparticle) of the present disclosure. In a further independent aspect, the present disclosure provides an RNA, carrier (preferably lipid nanoparticle) or pharmaceutical composition of the present disclosure, for use in medicine. In a further independent aspect, the present disclosure provides a method comprising administering an effective amount of the RNA, carrier (preferably lipid nanoparticle), or pharmaceutical composition of the present disclosure to a subject. In an embodiment of said aspect, the present disclosure provides a method of inducing an immune response against RSV in a subject, the method comprising administering an effective amount of the RNA, carrier (preferably lipid nanoparticle) or pharmaceutical composition of the present disclosure to a subject. Further exemplary independent aspects of the present disclosure are provided throughout the detailed description, below. DESCRIPTION OF FIGURES Figure 1. In vitro validation of mRNAs for in vivo study. Select mRNAs encoding RSV-F were forward transfected into primary BJ cell monolayers. The cell monolayers were fixed and RSV-F protein expression was evaluated by indirect immunofluorescence coupled with high content imaging and image analysis. The mRNAs encode RSV-F variants including DS-CAV1, F(ii), F(iii) and F(i) proteins. RSV-F surface protein expression was quantified 1 day post infection by labelling cells using the anti-RSV F antibodies Motavizumab (A), D25 (E) or AM14 (I) or 3 days post transfection (Motavizumab (C), D25 (G) or AM14 (K)). The average cell count for three imaged wells is shown and corresponds to the RSV-F expression values for 1 day post infection (Motavizumab (B), D25 (F) or AM14 (J) or 3 days post transfection (motavizumab (D), D25 (H) or AM14 (L)). Each graph depicts the mean (µ) +/- 1 standard deviation (σ) from 3 biological replicates as calculated by GraphPad Prism software. Figure 2. RSV pre-F IgG binding antibody geometric mean titres on day 21 (3wp1) and day 35 (2wp2) in animals immunized with (A) 2 μg or (B) 0.2 μg of RNA encoding F(iii), F(i), DS-Cav1 or F(ii) (where each point represents an individual animal). Docket No: 70330WO01 Figure 3. RSV A neutralizing antibody titres (ED60) on day 21 (3wp1) and day 35 (2wp2) in animals immunized with either (A) 2 μg or (B) 0.2 μg of RNA encoding F(iii), F(i), DS-Cav1 or F(ii) (where each point represents an individual animal). Figure 4. (A) RSV A neutralising antibody titres (ED60) on day 21 (3wp1) and day 35 (2wp2) in animals immunised with 0.5 μg of F(i), F(ii), F(iii) or DS-Cav1 (where each point represents an individual animal). (B) RSV A and B day 35 (2wp2) cross-neutralisation titres to lab-adapted (RSV A-long and RSV B-18537) and clinical RSV strains (RSV A-Clinical 2015, RSV B-Clinical 2015 and 2017). Figure 5. (A) pre-F and (B) post-F IgG binding antibody titers on day 21 and day 35 for constructs in Example 4. DETAILED DESCRIPTION RNA encoding an RSV-F protein The present disclosure provides, in an independent aspect, a recombinant RNA encoding an RSV-F protein comprising an F2 and an F1 domain; wherein the RSV-F protein further comprises, relative to a wild-type RSV-F sequence, the substitution of a residue for a C residue in both of the F2 and F1 domains. Said wild-type RSV-F sequence may be SEQ ID NO: 1 or 2. A further independent aspect of the present disclosure provides a recombinant RNA encoding an RSV-F protein comprising an F2 and an F1 domain; wherein the RSV-F protein further comprises, relative to SEQ ID NO: 1 or 2, the substitution of a residue for a C residue in both of the F2 and F1 domains. For the avoidance of doubt, such recombinant RNAs, and the RSV-F proteins which they encode, are respectively referred to herein as “RNA(s) of the present disclosure” and “RSV-F protein(s) of the present disclosure”. The wild-type RSV-F sequences of SEQ ID NO: 1 (A2 subtype), and SEQ ID NO: 2 (B subtype strain 18537) are not “RSV-F proteins of the present disclosure”, as referred to herein. RSV-F proteins of the present disclosure and the mutations which they comprise (relative to a wild- type RSV-F protein), are “engineered”, in the sense that such mutations have been deliberately selected and introduced into the proteins, at least in part in order to enhance expression from RNA and consequently immunogenicity. RSV-F proteins of the present disclosure may also be considered “recombinant” (“engineered” and “recombinant” may be used interchangeably in this context). SEQ ID NO: 1 is an RSV-F sequence from a strain of human RSV of the A2 subtype that contains two mutations (K66E and Q101P) relative to GenBank Accession number KT992094 (said mutations resulting from in vitro passaging, see [11]). SEQ ID NO: 2 is the RSV-F sequence from B subtype Docket No: 70330WO01 strain 18537 (Uniprot ID: P13843). SEQ ID NO:1, SEQ ID NO: 2, and any wild-type RSV-F sequence (e.g. RSV-F proteins of other A or B subtype strains) are referred to herein as “wild-type”. RSV-F proteins of the present disclosure may comprise mutations relative to SEQ ID NO: 1 or 2 found in RSV-F proteins from further strains and subtypes, both naturally-occurring and engineered (e.g. RSV- F proteins of further A subtype strains, or further B subtype strains). Hence, RSV-F proteins of the present disclosure may be of the RSV-A or the RSV-B subtype. RSV-F proteins of the present disclosure may also have a specific degree of sequence identity to SEQ ID NO: 1 or 2, e.g. as detailed in the embodiments below. “Mutation” is used generally herein to encompasses substitution, insertion and deletion of residues. Reference to a sequence / region of an RSV-F protein of the present disclosure “corresponding to positions x-y of SEQ ID NO: z” encompasses sequences / regions which align with positions x-y of SEQ ID NO: z (which, for the avoidance of doubt, includes positions x and y). Alignments may be performed visually, or by any well-known algorithm; e.g. using an NCBI BLAST algorithm, e.g. “blastp”, e.g. on default settings (available at https://blast.ncbi.nlm.nih.gov/Blast.cgi?PAGE=Proteins), or e.g. using the “Clustal Omega” algorithm (see, e.g. [12]), e.g. on default settings; with the Clustal Omega algorithm being preferred. Corresponding residue positions (e.g. position 103 of SEQ ID NO: 1, and so forth) are easily identifiable to the skilled person, and can be identified by aligning the amino acid sequences using any well-known method (visual or algorithm, e.g. as detailed above). Where there is no explicit reference to a reference sequence (e.g. SEQ ID NO: 1 or 2) when residue numbers are provided, standard residue numbering of RSV-F is to be used for the RSV-F protein in question (and such numbering will generally correspond with that of SEQ ID NO 1 or 2). RSV-F proteins of the present disclosure are preferably antigens when expressed (or, phrased differently, are antigenic). As such, RSV-F proteins of the present disclosure preferably elicit an immune response when administered to a subject (e.g. via expression from RNA), namely against RSV. The immune response may comprise an antibody response (usually including IgG) and/or a cell- mediated immune response, in particular an antibody response. The immune response will typically recognise the three-dimensional structure of a wild-type pre-fusion RSV-F, in particular one or more epitopes present on the (solvent-exposed) surface of the protein when in the pre-fusion conformation. RSV-F proteins of the present disclosure may also be considered antigens (or, phrased differently, are antigenic) given their ability to be bound by antibodies AM14, D25 and motavizumab; in particular AM14 which recognises trimeric, pre-fusion RSV-F (heavy and light chain sequences of antibodies given below). Docket No: 70330WO01 Generally, RSV-F proteins of the present disclosure may be considered as stabilised in the pre-fusion conformation, following expression from RNA. The pre-fusion conformation of RSV-F proteins of the present disclosure may be confirmed via binding of pre-fusion RSV-F-specific monoclonal antibodies (“pre-fusion mAbs”). For example, RSV-F proteins of the present disclosure may be specifically bound by a pre-fusion mAb comprising a light chain and a heavy chain (LC and HC) selected from the group consisting of: SEQ ID NO: 5 and 6 respectively, and SEQ ID NO: 7 and 8 respectively. The foregoing are the LC and HC sequences of prefusion mAbs AM14 and D25 (see, e.g. [13, 14]), with AM14 being preferred for confirming pre-fusion conformation. Specific mutations relative to a wild-type RSV-F sequence are present in RSV-F proteins of the present disclosure, which promote and/or stabilise the pre-fusion conformation, following expression from RNA. RSV-F proteins of the present disclosure may comprise an F2 and an F1 domain, and the substitution relative to a wild-type RSV-F sequence (e.g. SEQ ID NO: 1 or 2), of a residue for a C residue in both of the F2 and F1 domains. When expressed, the C residues form a disulphide bond connecting the F2 and F1 domains. Said disulphide bond is not present in wild-type RSV-F, and so may be considered “artificial” or “engineered”. Said C residues, and the disulphide bond formed thereby, generally promote and/or stabilise the pre-fusion conformation of RSV-F. For example, RSV-F proteins of the present disclosure may comprise a C residue at both of positions 55 and 188 (not present in wild-type). Alternatively, the C residue in the F1 domain may be within the fusion peptide of the RSV-F protein; optionally wherein the fusion peptide is the region corresponding to positions 137-157 of SEQ ID NO: 1 or 2. For example, the C residue may be within the region of the RSV-F protein corresponding to positions 143-153, 146-150 or 147-149 of SEQ ID NO: 1 or 2; and preferably at position 148 of the RSV-F protein. The C residue in the F2 domain may be within the region of the RSV-F protein corresponding to positions 99-105, 100-104 or 102-104 of SEQ ID NO: 1 or 2; and preferably at position 103 of the RSV-F protein. In addition, RSV-F proteins of the present disclosure may comprise the substitution (relative to a wild- type RSV-F sequence, e.g. SEQ ID NO: 1 or 2) of one or more small aliphatic or small polar residues that are buried in the pre-fusion conformation (in wild-type), for larger aliphatic or larger aromatic residues. Said small aliphatic or small polar residues may be, for example, a S, T, G, A, V, or R residue. Said larger aliphatic or larger aromatic residues may be, for example, a I, Y, L, H, M or W residue. Such substitutions generally further promote and/or stabilise the pre-fusion conformation. In such further embodiments, RSV-F proteins of the present disclosure may, for example, comprise: (i) substitution at position 190, 55, 62, 155, or 290 for I, Y, L, H, or M; Docket No: 70330WO01 (ii) substitution at position 54, 58, 189, 219, or 397 for I, Y, L, H, or M; (iii) substitution at position 151 for A or H; (iv) substitution at position 147 or 298 for I, L, H, or M; (v) substitution at position 164, 187, 192, 207, 220, 296, 300, or 495 for I, Y, H; or (vi) substitution at position 106 for W; wherein substitutions at position 190 according to (i) are preferred; wherein substitution at position 190 for I is a preferred substitution at said position. In addition to, or instead of, one or more substitutions of buried residues as defined above, RSV-F proteins of the present disclosure may comprise substitutions (relative to a wild-type RSV-F sequence, e.g. SEQ ID NO: 1 or 2) which reduce inter-protomer repulsive ionic interactions or increase inter- protomer attractive ionic interactions with E487 and D489 on an adjacent RSV-F protomer (when the RSV-F protein is in trimeric form). Such substitutions generally further promote and/or stabilise the pre-fusion conformation. In such further embodiments, RSV-F proteins of the present disclosure may comprise the substitution of a D or E residue for S, T, N, H, P, F, L or Q within the region of the RSV- F protein corresponding to positions 474-523 of SEQ ID NO: 1 or 2 (a.k.a. the heptad repeat B (“HRB”) domain), such as D486S/H/N/T/P or E487Q/T/S/L/H. In such further embodiments, RSV-F proteins of the present disclosure may, for example, comprise: (vii) substitution at position 82, 92, or 487 for D, F, Q, T, S, L, or H; (viii) substitution at position 315, 394, or 399 for F, M, R, S, L, I, Q, or T; (ix) substitution at position 392, 486, or 489 for H, S, N, T, or P; and/or (x) substitution at position 106 or 339 for F, Q, N, or W; wherein substitutions at position 486 according to (ix) are preferred; wherein substitution at position 486 for S is a preferred substitution at said position. In preferred embodiments, RSV-F proteins of the present disclosure comprise the substitutions (relative to a wild-type RSV-F sequence, e.g. SEQ ID NO: 1 or 2) 103C, 148C, 190I and 486S. Such RSV-F proteins may be of the RSV-A or RSV-B subtype. See, e.g. construct F(i) as tested in the examples (see, e.g., Example 2; Figures 2-3). Docket No: 70330WO01 In such preferred embodiments, RSV-F proteins of the present disclosure may comprise or consist of: (i) an amino acid sequence according to SEQ ID NO: 3; or (ii) an amino acid sequence at least 70%, 80%, 85%, 90%, 95%, 99% or 99.5% identical thereto and comprising the 103C, 148C, 190I, and 486S substitutions (relative to a wild-type RSV-F sequence, e.g. SEQ ID NO: 1 or 2). In other embodiments, RSV-F proteins of the present disclosure may comprise of consist of: (i) a portion of SEQ ID NO: 3, such as a portion at least 70%, 80%, 85%, 90%, 95%, 99% or 99.5% the length thereof and comprising the 103C, 148C, 190I, and 486S substitutions (relative to a wild-type RSV-F sequence, e.g. SEQ ID NO: 1 or 2); or (ii) an amino acid sequence at least 70%, 80%, 85%, 90%, 95%, 99% or 99.5% identical to such a portion which comprises the 103C, 148C, 190I, and 486S substitutions (relative to a wild- type RSV-F ectodomain, e.g. SEQ ID NO: 1 or 2). In addition, or alternatively, in such preferred embodiments, RSV-F proteins of the present disclosure may comprise an ectodomain comprising or consisting of: (i) an amino acid sequence according to positions 26-109 and 137-523 of SEQ ID NO: 3; or (ii) an amino acid sequence at least 70%, 80%, 85%, 90%, 95%, 99% or 99.5% identical thereto and comprising the 103C, 148C, 190I, and 486S substitutions (relative to a wild-type RSV-F ectodomain, e.g. positions 26-109 and 137-523 of SEQ ID NO: 1 or 2). In other embodiments, RSV- F proteins of the present disclosure may comprise an ectodomain comprising or consisting of: (i) a portion of positions 26-109 and 137-523 of SEQ ID NO: 3, such as a portion at least 70%, 80%, 85%, 90%, 95%, 99% or 99.5% the length thereof and comprising the 103C, 148C, 190I, and 486S substitutions (relative to a wild-type RSV-F ectodomain, e.g. positions 26-109 and 137-523 of SEQ ID NO: 1 or 2); or (ii) an amino acid sequence at least 70%, 80%, 85%, 90%, 95%, 99% or 99.5% identical to such a portion which comprises the 103C, 148C, 190I, and 486S substitutions (relative to a wild- type RSV-F ectodomain, e.g. positions 26-109 and 137-523 of SEQ ID NO: 1 or 2). In a mature RSV- F protein / ectodomain, the region corresponding to positions 110-136 of SEQ ID NO 1 or 2 (which may be positions 110-136 of the RSV-F protein) may be absent due to furin processing. Hence, reference to “an amino acid sequence” may refer to two non-contiguous amino acid chains. However, RNA of the present disclosure will typically encode an RSV-F protein of the present disclosure comprising the region corresponding to positions 110-136 of SEQ ID NO 1 or 2 (which may be positions 110-136 of the RSV-F protein). All of the above mutations preferably promote and/or stabilise the pre-fusion conformation of RSV-F. The present disclosure furthermore provides, in a further independent aspect, a recombinant RNA encoding an RSV-F protein, wherein the RSV-F protein comprises: a C residue at position 103, a C residue at position 148, an I residue at position 190, and an S residue at position 486. Such recombinant RNAs, and the RSV-F proteins which it encodes, are also referred to herein as “RNA(s) of the present disclosure” and “RSV-F protein(s) of the present disclosure”. When expressed, the C residues Docket No: 70330WO01 generally form a disulphide bond which is not present in wild-type RSV-F. Said disulphide bond may be considered “artificial” or “engineered”. Said C residues, and the disulphide bond formed thereby, promote and/or stabilise the pre-fusion conformation of RSV-F. Such RSV-F proteins of the present disclosure may also be of the RSV-A or the RSV-B subtype. RSV-F proteins of the present disclosure may comprise or consist of an amino acid sequence having at least 70%, 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or preferably at least 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, or 99.5% sequence identity to SEQ ID NO: 1 or 2. In addition, or alternatively, the F2 domain may comprise or consist of an amino acid sequence having at least 70% sequence identity to positions 26-109 of SEQ ID NO: 1 or 2, such as at least 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or preferably at least 95%, 96%, 97%, 98%, or 99% sequence identity to positions 26-109 of SEQ ID NO: 1 or 2; and the F1 domain may comprise or consist of an amino acid sequence having at least 70% sequence identity to positions 137-523 of SEQ ID NO: 1 or 2, such as at least 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or preferably at least 95%, 96%, 97%, 98%, 99%, 99.2%, or 99.5% sequence identity to positions 137- 523 of SEQ ID NO: 1 or 2. In some embodiments, RSV-F proteins of the present disclosure comprise an E residue at position 66, and a P residue at position 101. In some embodiments, the signal peptide (positions 1-25 of SEQ ID NO: 1 and 2) is not considered in the above sequence identity assessment. Hence, RSV-F proteins of the present disclosure may comprise an amino acid sequence having at least 70% sequence identity to positions 26-574 SEQ ID NO: 1 or 2, such as at least 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or preferably at least 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, or 99.5% sequence identity to positions 26-574 SEQ ID NO: 1 or 2. Two furin cleavage sites exist between positions 109 and 137 of SEQ ID NO: 1, 2 and 3 (positions 110-136 of SEQ ID NO: 1 and 2 defining the “p27” peptide). In some embodiments, RNA of the present disclosure may encode an RSV-F protein of the present disclosure in which the p27 peptide is artificially absent (i.e. there is an artificial deletion of the p27 peptide, e.g. through recombinant means, at the level of the encoding RNA). In such embodiments, the fusion peptide (e.g. positions 137-157 of SEQ ID NO: 1 or 2) may also be artificially absent. In some embodiments, the p27 peptide (and, optionally, also the fusion peptide) may be replaced by a linker sequence encoded by the RNA. The linker sequence may be glycine-serine rich (or consist of G and S residues), for example GSGSG (SEQ ID NO: 11), GSGSGRS (SEQ ID NO: 12), GS (SEQ ID NO: 13), or GSGSGR (SEQ ID NO: 14). In Docket No: 70330WO01 one particular embodiment, the p27 peptide (or at least 80%, 85%, 90% or 95% of the residues thereof) is artificially absent and is replaced by a linker comprising or consisting of SEQ ID NO: 11, 12, 13 or 14 (or a linker having at least 55%, 75% or 85% identity thereto). In an alternative particular embodiment, both the p27 and fusion peptides (or at least 80%, 85%, 90% or 95% of the residues thereof) are artificially absent and are replaced by a linker comprising or consisting of SEQ ID NO: 13 (or either a G or an S residue). RSV-F proteins of the present disclosure may comprise or consist of an amino acid sequence having at least 70% sequence identity to SEQ ID NO: 1 over at least 80% of SEQ ID NO: 1; in particular at least 75% sequence identity to SEQ ID NO: 1 over at least 80% of SEQ ID NO: 1, at least 80% sequence identity to SEQ ID NO: 1 over at least 80% of SEQ ID NO: 1, at least 85% sequence identity to SEQ ID NO: 1 over at least 80% of SEQ ID NO: 1, at least 90% sequence identity to SEQ ID NO: 1 over at least 80% of SEQ ID NO: 1, at least 95% sequence identity to SEQ ID NO: 1 over at least 80% of SEQ ID NO: 1, at least 99% sequence identity to SEQ ID NO: 1 over at least 80% of SEQ ID NO: 1, at least 99.4% sequence identity to SEQ ID NO: 1 over at least 80% of SEQ ID NO: 1, at least 99.5% sequence identity to SEQ ID NO: 1 over at least 80% of SEQ ID NO: 1, at least 75% sequence identity to SEQ ID NO: 1 over at least 90% of SEQ ID NO: 1, at least 80% sequence identity to SEQ ID NO: 1 over at least 90% of SEQ ID NO: 1, at least 85% sequence identity to SEQ ID NO: 1 over at least 90% of SEQ ID NO: 1, at least 90% sequence identity to SEQ ID NO: 1 over at least 90% of SEQ ID NO: 1, at least 95% sequence identity to SEQ ID NO: 1 over at least 90% of SEQ ID NO: 1, at least 99% sequence identity to SEQ ID NO: 1 over at least 90% of SEQ ID NO: 1, at least 99.4% sequence identity to SEQ ID NO: 1 over at least 90% of SEQ ID NO: 1, at least 99.5% sequence identity to SEQ ID NO: 1 over at least 90% of SEQ ID NO: 1, at least 75% sequence identity to SEQ ID NO: 1 over at least 95% of SEQ ID NO: 1, at least 80% sequence identity to SEQ ID NO: 1 over at least 95% of SEQ ID NO: 1, at least 85% sequence identity to SEQ ID NO: 1 over at least 95% of SEQ ID NO: 1, at least 90% sequence identity to SEQ ID NO: 1 over at least 95% of SEQ ID NO: 1, at least 95% sequence identity to SEQ ID NO: 1 over at least 95% of SEQ ID NO: 1, at least 99% sequence identity to SEQ ID NO: 1 over at least 95% of SEQ ID NO: 1, at least 99.4% sequence identity to SEQ ID NO: 1 over at least 95% of SEQ ID NO: 1, or at least 99.5% sequence identity to SEQ ID NO: 1 over at least 95% of SEQ ID NO: 1. RSV-F proteins of the present disclosure may comprise or consist of an amino acid sequence having at least 70% sequence identity to SEQ ID NO: 2 over at least 80% of SEQ ID NO: 2; in particular at least 75% sequence identity to SEQ ID NO: 2 over at least 80% of SEQ ID NO: 2, at least 80% sequence identity to SEQ ID NO: 2 over at least 80% of SEQ ID NO: 2, at least 85% sequence identity to SEQ ID NO: 2 over at least 80% of SEQ ID NO: 2, at least 90% sequence identity to SEQ ID NO: Docket No: 70330WO01 2 over at least 80% of SEQ ID NO: 2, at least 95% sequence identity to SEQ ID NO: 2 over at least 80% of SEQ ID NO: 2, at least 99% sequence identity to SEQ ID NO: 2 over at least 80% of SEQ ID NO: 2, at least 99.4% sequence identity to SEQ ID NO: 2 over at least 80% of SEQ ID NO: 2, at least 99.5% sequence identity to SEQ ID NO: 2 over at least 80% of SEQ ID NO: 2, at least 75% sequence identity to SEQ ID NO: 2 over at least 90% of SEQ ID NO: 2, at least 80% sequence identity to SEQ ID NO: 2 over at least 90% of SEQ ID NO: 2, at least 85% sequence identity to SEQ ID NO: 2 over at least 90% of SEQ ID NO: 2, at least 90% sequence identity to SEQ ID NO: 2 over at least 90% of SEQ ID NO: 2, at least 95% sequence identity to SEQ ID NO: 2 over at least 90% of SEQ ID NO: 2, at least 99% sequence identity to SEQ ID NO: 2 over at least 90% of SEQ ID NO: 2, at least 99.4% sequence identity to SEQ ID NO: 2 over at least 90% of SEQ ID NO: 2, at least 99.5% sequence identity to SEQ ID NO: 2 over at least 90% of SEQ ID NO: 2, at least 75% sequence identity to SEQ ID NO: 2 over at least 95% of SEQ ID NO: 2, at least 80% sequence identity to SEQ ID NO: 2 over at least 95% of SEQ ID NO: 2, at least 85% sequence identity to SEQ ID NO: 2 over at least 95% of SEQ ID NO: 2, at least 90% sequence identity to SEQ ID NO: 2 over at least 95% of SEQ ID NO: 2, at least 95% sequence identity to SEQ ID NO: 2 over at least 95% of SEQ ID NO: 2, at least 99% sequence identity to SEQ ID NO: 2 over at least 95% of SEQ ID NO: 2, at least 99.4% sequence identity to SEQ ID NO: 2 over at least 95% of SEQ ID NO: 2, or at least 99.5% sequence identity to SEQ ID NO: 2 over at least 95% of SEQ ID NO: 1. RSV-F proteins of the present disclosure may comprise or consist of an amino acid sequence having at least 70% sequence identity to SEQ ID NO: 1, such as at least 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or preferably at least 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, or 99.5% sequence identity to SEQ ID NO: 1 over 100% of SEQ ID NO 1. RSV-F proteins of the present disclosure may comprise or consist of an amino acid sequence having at least 70% sequence identity to SEQ ID NO: 2, such as at least 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or preferably at least 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, or 99.5% sequence identity to SEQ ID NO: 2 over 100% of SEQ ID NO 2. RNA of the present disclosure preferably encodes an RSV-F protein of the present disclosure comprising a transmembrane domain, and, optionally, C-terminal to said transmembrane domain, a cytoplasmic tail. In some embodiments, a cytoplasmic tail is absent in whole. Preferably, a transmembrane domain comprises or consists of an amino acid sequence according to positions 524- 549 or 525-549 of SEQ ID NO: 1 or 2 (or a sequence at least 80%, 85%, 90%, or 95% identical thereto). Docket No: 70330WO01 Preferably, a cytoplasmic tail, if present, comprises or consists of an amino acid sequence according to positions 550-574 of SEQ ID NO: 1 or 2 (or a sequence at least 80%, 85%, 90%, 95% or 95% identical thereto). Generally, RNA of the present disclosure, and the RSV-F proteins encoded thereby, elicit a pre-fusion RSV-F-specific antibody response against RSV in vivo, e.g. an IgG antibody response (see, e.g. Example 2). Generally, RNA of the present disclosure, and the RSV-F proteins encoded thereby, elicit a neutralising antibody response against RSV in vivo, e.g. against RSV-A (see, e.g. Example 2). Said neutralising antibody response may inhibit replication of RSV in the respiratory system of a subject (such as in the lungs). Said neutralising antibody response may yield protective immunity against RSV in a subject. Generally, RNA of the present disclosure, and the RSV-F proteins encoded thereby, elicit a cross- neutralising antibody response against RSV in vivo, e.g. against strains of both RSV-A and RSV-B subtypes (see, e.g. Example 4). Said cross-neutralising antibody response may inhibit replication of RSV (e.g. strains of both RSV-A and RSV-B subtypes) in the respiratory system of a subject (such as in the lungs). Said cross-neutralising antibody response may yield protective immunity against RSV (e.g. strains of both RSV-A and RSV-B subtypes) in a subject. General features of RNA of the present disclosure “RNA” refers to a ribonucleic acid encoding an RSV-F protein of the present disclosure, which may be translated in a cell (i.e. mRNA). Preferably, the RNA is neither, nor comprised within, a viral vector or virus-based vaccine (such as a live-attenuated virus vaccine). RNA molecules can have various lengths but are typically 500-20,000 ribonucleotides long e.g.1000- 20,000, 1000-15,000, 1000-10,000, 1000-5000, 1000-3000, 1000-2500, 1000-2500 or 1000-2000 ribonucleotides long. The RNA can be non-self-replicating (also referred to as “conventional” RNA), or self-replicating; preferably non-self-replicating. In some embodiments, the RNA is self-replicating. Self-replicating RNA can be produced using replication elements derived from, e.g., alphaviruses, and substituting sequences encoding the structural viral proteins with that encoding at least an RSV-F protein of the present disclosure. A self- replicating RNA molecule is typically a positive-strand molecule which can be directly translated after delivery to a cell, and this translation provides an RNA-dependent RNA polymerase which then produces both antisense and sense transcripts from the delivered RNA. Thus, the delivered RNA leads to the production of multiple daughter RNAs. These daughter RNAs, as well as collinear subgenomic transcripts, may be translated themselves to provide in situ expression of the encoded protein (i.e. the Docket No: 70330WO01 RSV-F protein of the present disclosure); or may be transcribed to provide further transcripts with the same sense as the delivered RNA, which are translated to provide in situ expression of the encoded protein. The overall result of this sequence of transcriptions is substantial amplification in the number of the introduced RNAs, and so the encoded RSV-F protein of the present disclosure (potentially in addition to further proteins as detailed above) becomes a major polypeptide product of the cells. In such embodiments wherein the RNA is self-replicating, it may encode (i) an RNA-dependent RNA polymerase which can transcribe RNA from the self-replicating RNA and (ii) an RSV-F protein of the present disclosure. The polymerase can be an alphavirus replicase e.g. comprising one or more of alphavirus proteins nsP1, nsP2, nsP3 and nsP4. Such alphavirus-based self-replicating RNA can use a replicase from, for example, a Sindbis virus, a Semliki forest virus, an eastern equine encephalitis virus (EEEV), or a Venezuelan equine encephalitis virus (VEEV). Mutant or wild-type virus sequences can be used e.g. the attenuated TC83 mutant of VEEV has been used for self-replicating RNA (see [15]). Thus, a self-replicating RNA encoding an RSV-F protein of the present disclosure may have two open reading frames. The first (5') open reading frame encodes a replicase, in particular an alphavirus replicase (e.g. as detailed above); the second (3') open reading frame encodes the RSV-F protein of the present disclosure. Further open reading frames may also be present, encoding (i) one or more further proteins (preferably one or more further antigens, e.g. as detailed above); and/or (ii) accessory polypeptides. Generally, the RNA comprises a 5’ cap, such as a 7-methylguanosine, which may be added via enzymatic means or a non-enzymatic reaction. The RNA may have the following exemplary 5’ caps: - a 7-methylguanosine linked 5’-to-5’ to the 5’ first ribonucleotide by a triphosphate bridge (also referred to as “Cap O”); - a 7-methylguanosine linked 5’-to-5’ to the 5’ first ribonucleotide by a triphosphate bridge, and wherein the first 5’ ribonucleotide comprises a 2’-methylated ribose (2’-O-Me) (also referred to as “Cap 1”); - a 7-methyl-3'-O-methylguanosine linked 5’-to-5’ to the 5’ first ribonucleoside by a triphosphate bridge, and wherein the first 5’ ribonucleoside comprises a 2’-methylated ribose (2’-O-Me) (also referred to as “Cap 1”); - a 7-methylguanosine linked 5’-to-5’ to the 5’ first ribonucleotides by a triphosphate bridge, and wherein the first and second 5’ ribonucleotides comprise a 2’-methylated ribose (2’-O-Me) (also referred to as “Cap 2”); Docket No: 70330WO01 - or a 7-methylguanosine linked 5’-to-5’ to the 5’ first ribonucleotides by a triphosphate bridge, and wherein the first, second and third 5’ ribonucleotides comprise a 2’-methylated ribose (2’- O-Me). In a preferred embodiment, the 5’ cap is a 7-methylguanosine linked 5’-to-5’ to the 5’ first ribonucleoside by a triphosphate bridge, and wherein the first 5’ ribonucleoside comprises a 2’- methylated ribose (2’-O-Me), e.g. the 5’ end of the RNA has the structure m7G(5')ppp(5')(2'OMeA)pG. Preferably, this cap is added non-enzymatically through the use of the following reagent:

Said reagent is sold as CLEANCAP Reagent AG (TRILINK BIOTECHNOLOGIES). In another preferred embodiment, the 5’ cap is a 7-methyl-3'-O-methylguanosine linked 5’-to-5’ to the 5’ first ribonucleoside by a triphosphate bridge, and wherein the first 5’ ribonucleoside comprises a 2’- methylated ribose (2’-O-Me), e.g. the 5’ end of the RNA has the structure m7(3'OMeG)(5')ppp(5')(2'OMeA)pG. This cap may be added non-enzymatically through the use of the following reagent: Docket No: 70330WO01

Said reagent is sold as CLEANCAP Reagent AG (3’OMe) (TRILINK BIOTECHNOLOGIES) Generally, the RNA comprises a 3’ poly-adenosine (“poly-A”) tail, e.g. comprising 10-700 A ribonucleotides. The poly-A tail may comprise (i) a (in particular, only one) contiguous stretch of A ribonucleotides; or preferably (ii) at least two non-contiguous stretches of A ribonucleotides (also referred to as a “split poly-A tail”), such as only two non-contiguous stretches of A ribonucleotides. The total number of A ribonucleotides (“As”) in at least two non-contiguous stretches (such as only two non-contiguous stretches) may be, for example, 10-700, such as 10-600, 10-500, 20-500, 50-500, 70-500, 100-500, 20-400, 30-300, 40-200, 50-150, 70-120, 100-120, or, in particular, 100-120. The total number of As in a (in particular, only one) contiguous stretch may be, for example, 10-700; such as 10-600, 20-600 or in particular 40-600 (such as 50-600, 80-600, 80-550, 100-500; or 40-70, 50-65 or 55-65). Wherein at least two non-contiguous stretches of As are used, these may be of differing length. For example, a first stretch may be 10-150 As in length, such as 10-100, 10-50, 15-50, 20-50, 20-40, 25-40, or, in particular 25-35 As in length. For example, a second stretch may be 10-150 As in length, such as 10-150, 20-120, 30-100, 40-90, 50-90, 60-90, 65-90, 70-90, or, in particular, 80-90 As in length. The first stretch may be located 5’ or 3’ relative to the second stretch. However, in a particular embodiment, the first stretch is located 5’ relative to the second stretch. In a further particular embodiment, the polyA tail comprises, in the 5’ to 3’ direction, a first and a second non-contiguous stretch of As, that are 25-35 and 80-90 As in length respectively. In a further particular embodiment, the polyA tail comprises, in the 5’-3’ direction, a first and a second non-contiguous stretch of As, that are 25-35 and 65-90 As in length respectively. In some embodiments, the at least two non-contiguous stretches of As is from, or is part of, the 3’ untranslated region (UTR), e.g. as detailed below. The RNA preferably comprises (in addition to any 5' cap structure) one or more modified ribonucleotides, i.e. ribonucleotides that are modified in structure relative to standard A, C, G or U Docket No: 70330WO01 ribonucleotides. In other embodiments, the RNA does not comprise modified ribonucleotides, i.e. the RNA contains standard A, C, G or U ribonucleotides only (except for any 5’ cap structure, if present, e.g. as detailed above). In preferred embodiments wherein one or more modified ribonucleotides are used, said one or more modified ribonucleotides may be, or may comprise, N1-methylpseudouridine (“1mΨ”); pseudouridine (“Ψ”); N1-ethylpseudouridine; 2-methylthio-N6-(cis- hydroxyisopentenyl)adenosine; 2-methylthio-N6-methyladenosine; 2-methylthio-N6-threonyl carbamoyladenosine; N6-glycinylcarbamoyladenosine; N6-isopentenyladenosine; N6- methyladenosine (m6A); N6-threonylcarbamoyladenosine; 1,2'-O-dimethyladenosine; 1- methyladenosine; 2'-O-methyladenosine; 2'-O-ribosyladenosine (phosphate); 2-methyladenosine; 2- methylthio-N6 isopentenyladenosine; 2-methylthio-N6-hydroxynorvalyl carbamoyladenosine; 2'-O- methyladenosine; 2'-O-ribosyladenosine (phosphate); Isopentenyladenosine; N6-(cis- hydroxyisopentenyl)adenosine; N6,2'-O-dimethyladenosine; N6,2'-O-dimethyladenosine; N6,N6,2'- O-trimethyladenosine; N6,N6-dimethyladenosine; N6-acetyladenosine; N6- hydroxynorvalylcarbamoyladenosine; N6-methyl-N6-threonylcarbamoyladenosine; 2- methyladenosine; 2-methylthio-N6-isopentenyladenosine; 7-deaza-adenosine; N1-methyl-adenosine; N6,N6 (dimethyl)adenine; N6-cis-hydroxy-isopentenyl-adenosine; .alpha.-thio-adenosine; 2 (amino)adenine; 2 (aminopropyl)adenine; 2 (methylthio) N6 (isopentenyl)adenine; 2-(alkyl)adenine; 2-(aminoalkyl)adenine; 2-(aminopropyl)adenine; 2-(halo)adenine; 2-(halo)adenine; 2- (propyl)adenine; 2'-Amino-2'-deoxy-ATP; 2'-Azido-2'-deoxy-ATP; 2'-Deoxy-2'-a-aminoadenosine TP; 2'-Deoxy-2'-a-azidoadenosine TP; 6 (alkyl)adenine; 6 (methyl)adenine; 6-(alkyl)adenine; 6- (methyl)adenine; 7 (deaza)adenine; 8 (alkenyl)adenine; 8 (alkynyl)adenine; 8 (amino)adenine; 8 (thioalkyl)adenine; 8-(alkenyl)adenine; 8-(alkyl)adenine; 8-(alkynyl)adenine; 8-(amino)adenine; 8- (halo)adenine; 8-(hydroxyl)adenine; 8-(thioalkyl)adenine; 8-(thiol)adenine; 8-azido-adenosine; aza adenine; deaza adenine; N6 (methyl)adenine; N6-(isopentyl)adenine; 7-deaza-8-aza-adenosine; 7- methyladenine; 1-Deazaadenosine TP; 2'Fluoro-N6-Bz-deoxyadenosine TP; 2'-OMe-2-Amino-ATP; 2'O-methyl-N6-Bz-deoxyadenosine TP; 2'-a-Ethynyladenosine TP; 2-aminoadenine; 2- Aminoadenosine TP; 2-Amino-ATP; 2'-a-Trifluoromethyladenosine TP; 2-Azidoadenosine TP; 2'-b- Ethynyladenosine TP; 2-Bromoadenosine TP; 2'-b-Trifluoromethyladenosine TP; 2-Chloroadenosine TP; 2'-Deoxy-2',2'-difluoroadenosine TP; 2'-Deoxy-2'-a-mercaptoadenosine TP; 2'-Deoxy-2'-a- thiomethoxyadenosine TP; 2'-Deoxy-2'-b-aminoadenosine TP; 2'-Deoxy-2'-b-azidoadenosine TP; 2'- Deoxy-2'-b-bromoadenosine TP; 2'-Deoxy-2'-b-chloroadenosine TP; 2'-Deoxy-2'-b-fluoroadenosine TP; 2'-Deoxy-2'-b-iodoadenosine TP; 2'-Deoxy-2'-b-mercaptoadenosine TP; 2'-Deoxy-2'-b- thiomethoxyadenosine TP; 2-Fluoroadenosine TP; 2-Iodoadenosine TP; 2-Mercaptoadenosine TP; 2- methoxy-adenine; 2-methylthio-adenine; 2-Trifluoromethyladenosine TP; 3-Deaza-3-bromoadenosine TP; 3-Deaza-3-chloroadenosine TP; 3-Deaza-3-fluoroadenosine TP; 3-Deaza-3-iodoadenosine TP; 3- Docket No: 70330WO01 Deazaadenosine TP; 4'-Azidoadenosine TP; 4'-Carbocyclic adenosine TP; 4'-Ethynyladenosine TP; 5'- Homo-adenosine TP; 8-Aza-ATP; 8-bromo-adenosine TP; 8-Trifluoromethyladenosine TP; 9- Deazaadenosine TP; 2-aminopurine; 7-deaza-2,6-diaminopurine; 7-deaza-8-aza-2,6-diaminopurine; 7- deaza-8-aza-2-aminopurine; 2,6-diaminopurine; 7-deaza-8-aza-adenine, 7-deaza-2-aminopurine; 2- thiocytidine; 3-methylcytidine; 5-formylcytidine; 5-hydroxymethylcytidine; 5-methylcytidine; N4- acetylcytidine; 2'-O-methylcytidine; 2'-O-methylcytidine; 5,2'-O-dimethylcytidine; 5-formyl-2'-O- methylcytidine; Lysidine; N4,2'-O-dimethylcytidine; N4-acetyl-2'-O-methylcytidine; N4- methylcytidine; N4,N4-Dimethyl-2'-OMe-Cytidine TP; 4-methylcytidine; 5-aza-cytidine; Pseudo-iso- cytidine; pyrrolo-cytidine; .alpha.-thio-cytidine; 2-(thio)cytosine; 2'-Amino-2'-deoxy-CTP; 2'-Azido- 2'-deoxy-CTP; 2'-Deoxy-2'-a-aminocytidine TP; 2'-Deoxy-2'-a-azidocytidine TP; 3 (deaza) 5 (aza)cytosine; 3 (methyl)cytosine; 3-(alkyl)cytosine; 3-(deaza) 5 (aza)cytosine; 3-(methyl)cytidine; 4,2'-O-dimethylcytidine; 5 (halo)cytosine; 5 (methyl)cytosine; 5 (propynyl)cytosine; 5 (trifluoromethyl)cytosine; 5-(alkyl)cytosine; 5-(alkynyl)cytosine; 5-(halo)cytosine; 5- (propynyl)cytosine; 5-(trifluoromethyl)cytosine: 5-bromo-cytidine; 5-iodo-cytidine; 5-propynyl cytosine; 6-(azo)cytosine; 6-aza-cytidine; aza cytosine; deaza cytosine; N4 (acetyl)cytosine; 1-methyl- 1-deaza-pseudoisocytidine; 1-methyl-pseudoisocytidine; 2-methoxy-5-methyl-cytidine: 2-methoxy- cytidine; 2-thio-5-methyl-cytidine; 4-methoxy-1-methyl-pseudoisocytidine; 4-methoxy- pseudoisocytidine; 4-thio-1-methyl-1-deaza-pseudoisocytidine; 4-thio-1-methyl-pseudoisocytidine; 4- thio-pseudoisocytidine; 5-aza-zebularine; 5-methyl-zebularine; pyrrolo-pseudoisocytidine; Zebularine; (E)-5-(2-Bromo-vinyl)cytidine TP; 2,2'-anhydro-cytidine TP hydrochloride; 2'Fluor-N4- Bz-cytidine TP; 2'Fluoro-N4-Acetyl-cytidine TP; 2'-O-Methyl-N4-Acetyl-cytidine TP; 2'O-methyl- N4-Bz-cytidine TP; 2'-a-Ethynylcytidine TP; 2'-a-Trifluoromethylcytidine TP; 2'-b-Ethynylcytidine TP; 2'-b-Trifluoromethylcytidine TP; 2'-Deoxy-2',2'-difluorocytidine TP; 2'-Deoxy-2'-a- mercaptocytidine TP; 2'-Deoxy-2'-a-thiomethoxycytidine TP; 2'-Deoxy-2'-b-aminocytidine TP; 2'- Deoxy-2'-b-azidocytidine TP; 2'-Deoxy-2'-b-bromocytidine TP; 2'-Deoxy-2'-b-chlorocytidine TP; 2'- Deoxy-2'-b-fluorocytidine TP; 2'-Deoxy-2'-b-iodocytidine TP; 2'-Deoxy-2'-b-mercaptocytidine TP; 2'- Deoxy-2'-b-thiomethoxycytidine TP; 2'-O-Methyl-5-(1-propynyl)cytidine TP; 3'-Ethynylcytidine TP; 4'-Azidocytidine TP; 4'-Carbocyclic cytidine TP; 4'-Ethynylcytidine TP; 5-(1-Propynyl)ara-cytidine TP; 5-(2-Chloro-phenyl)-2-thiocytidine TP; 5-(4-Amino-phenyl)-2-thiocytidine TP; 5-Aminoallyl- CTP; 5-Cyanocytidine TP; 5-Ethynylara-cytidine TP; 5-Ethynylcytidine TP; 5'-Homo-cytidine TP; 5- Methoxycytidine TP; 5-Trifluoromethyl-Cytidine TP; N4-Amino-cytidine TP; N4-Benzoyl-cytidine TP; Pseudoisocytidine; 7-methylguanosine; N2,2'-O-dimethylguanosine; N2-methylguanosine; Wyosine; 1,2'-O-dimethylguanosine; 1-methylguanosine; 2'-O-methylguanosine; 2'-O- ribosylguanosine (phosphate); 2'-O-methylguanosine; 2'-O-ribosylguanosine (phosphate); 7- aminomethyl-7-deazaguanosine; 7-cyano-7-deazaguanosine; Archaeosine; Methylwyosine; N2,7- Docket No: 70330WO01 dimethylguanosine; N2,N2,2'-O-trimethylguanosine; N2,N2,7-trimethylguanosine; N2,N2- dimethylguanosine; N2,7,2'-O-trimethylguanosine; 6-thio-guanosine; 7-deaza-guanosine; 8-oxo- guanosine; N1-methyl-guanosine; .alpha.-thio-guanosine; 2 (propyl)guanine; 2-(alkyl)guanine; 2'- Amino-2'-deoxy-GTP; 2'-Azido-2'-deoxy-GTP; 2'-Deoxy-2'-a-aminoguanosine TP; 2'-Deoxy-2'-a- azidoguanosine TP; 6 (methyl)guanine; 6-(alkyl)guanine; 6-(methyl)guanine; 6-methyl-guanosine; 7 (alkyl)guanine; 7 (deaza)guanine; 7 (methyl)guanine; 7-(alkyl)guanine; 7-(deaza)guanine; 7- (methyl)guanine; 8 (alkyl)guanine; 8 (alkynyl)guanine; 8 (halo)guanine; 8 (thioalkyl)guanine; 8- (alkenyl)guanine; 8-(alkyl)guanine; 8-(alkynyl)guanine; 8-(amino)guanine; 8-(halo)guanine; 8- (hydroxyl)guanine; 8-(thioalkyl)guanine; 8-(thiol)guanine; aza guanine; deaza guanine; N (methyl)guanine; N-(methyl)guanine; 1-methyl-6-thio-guanosine; 6-methoxy-guanosine; 6-thio-7- deaza-8-aza-guanosine; 6-thio-7-deaza-guanosine; 6-thio-7-methyl-guanosine; 7-deaza-8-aza- guanosine; 7-methyl-8-oxo-guanosine; N2,N2-dimethyl-6-thio-guanosine; N2-methyl-6-thio- guanosine; 1-Me-GTP; 2'Fluoro-N2-isobutyl-guanosine TP; 2'O-methyl-N2-isobutyl-guanosine TP; 2'-a-Ethynylguanosine TP; 2'-a-Trifluoromethylguanosine TP; 2'-b-Ethynylguanosine TP; 2'-b- Trifluoromethylguanosine TP; 2'-Deoxy-2',2'-difluoroguanosine TP; 2'-Deoxy-2'-a- mercaptoguanosine TP; 2'-Deoxy-2'-a-thiomethoxyguanosine TP; 2'-Deoxy-2'-b-aminoguanosine TP; 2'-Deoxy-2'-b-azidoguanosine TP; 2'-Deoxy-2'-b-bromoguanosine TP; 2'-Deoxy-2'-b- chloroguanosine TP; 2'-Deoxy-2'-b-fluoroguanosine TP; 2'-Deoxy-2'-b-iodoguanosine TP; 2'-Deoxy- 2'-b-mercaptoguanosine TP; 2'-Deoxy-2'-b-thiomethoxyguanosine TP; 4'-Azidoguanosine TP; 4'- Carbocyclic guanosine TP; 4'-Ethynylguanosine TP; 5'-Homo-guanosine TP; 8-bromo-guanosine TP; 9-Deazaguanosine TP; N2-isobutyl-guanosine TP; 1-methylinosine; Inosine; 1,2'-O-dimethylinosine; 2'-O-methylinosine; 7-methylinosine; 2'-O-methylinosine; Epoxyqueuosine; galactosyl-queuosine; Mannosylqueuosine; Queuosine; allyamino-thymidine; aza thymidine; deaza thymidine; deoxy- thymidine; 2'-O-methyluridine; 2-thiouridine; 3-methyluridine; 5-carboxymethyluridine; 5- hydroxyuridine; 5-methyluridine; 5-taurinomethyl-2-thiouridine; 5-taurinomethyluridine; Dihydrouridine; (3-(3-amino-3-carboxypropyl)uridine; 1-methyl-3-(3-amino-5- carboxypropyl)pseudouridine; 1-methylpseduouridine; 1-methyl-pseudouridine; 2'-O-methyluridine; 2'-O-methylpseudouridine; 2'-O-methyluridine; 2-thio-2'-O-methyluridine; 3-(3-amino-3- carboxypropyl)uridine; 3,2'-O-dimethyluridine; 3-Methyl-pseudo-Uridine TP; 4-thiouridine; 5- (carboxyhydroxymethyl)uridine; 5-(carboxyhydroxymethyl)uridine methyl ester, 5,2'-O- dimethyluridine; 5,6-dihydro-uridine; 5-aminomethyl-2-thiouridine; 5-carbamoylmethyl-2'-O- methyluridine; 5-carbamoylmethyluridine; 5-carboxyhydroxymethyluridine; 5- carboxyhydroxymethyluridine methyl ester, 5-carboxymethylaminomethyl-2'-O-methyluridine; 5- carboxymethylaminomethyl-2-thiouridine; 5-carboxymethylaminomethyl-2-thiouridine; 5- caboxymethylaminomethyluridine; 5-carboxymethylaminomethyluridine; 5-Carbamoylmethyluridine Docket No: 70330WO01 TP; 5-methoxycaeoonylmethyl-2'-O-methyluridine; 5-methoxycarbonylmethyl-2-thiouridine; 5- methoxycarbonylmethyluridine; 5-methoxyuridine; 5-methyl-2-thiouridine; 5-methylaminomethyl-2- selenouridine; 5-methylaminomethyl-2-thiouridine; 5-methylaminomethyluridine; 5- Methyldihydrouridine; 5-Oxyacetic acid-Uridine TP; 5-Oxyacetic acid-methyl ester-Uridine TP; N1- methyl-pseudo-uridine; N1-ethyl-pseudo-uridine; uridine 5-oxyacetic acid; uridine 5-oxyacetic acid methyl ester; 3-(3-Amino-3-carboxypropyl)-Uridine TP; 5-(iso-Pentenylaminomethyl)-2-thiouridine TP; 5-(iso-Pentenylaminomethyl)-2'-O-methyluridine TP; 5-(iso-Pentenylaminomethyl)uridine TP; 5- propynyl uracil; .alpha.-thio-uridine; 1 (aminoalkylamino-carbonylethylenyl)-2(thio)-pseudouridine; 1 (aminoalkylaminocarbonylethylenyl)-2,4-(dithio)pseudouridine; 1 (aminoalkylaminocarbonylethylenyl)-4 (thio)pseudouridine; 1 (aminoalkylaminocarbonylethylenyl)- pseudouridine; 1 (aminocazbonylethylenyl)-2(thio)-pseudouridine; 1 (aminocarbonylethylenyl)-2,4- (dithio)pseudouridine; 1 (aminocarbonylethylenyl)-4 (thio)pseudouridine; 1 (aminocarbonylethylenyl)-pseudouridine; 1 substituted 2(thio)-pseudouridine; 1 substituted 2,4- (dithio)pseudouridine; 1 substituted 4 (thio)pseudouridine; 1 substituted pseudouridine; 1- (aminoalkylamino-carbonylethylenyl)-2-(thio)-pseudouridine; 1-Methyl-3-(3-amino-3- carboxypropyl) pseudouridine TP; 1-Methyl-3-(3-amino-3-carboxypropyl)pseudo-UTP; 1-Methyl- pseudo-UTP; 2 (thio)pseudouridine; 2' deoxy uridine; 2' fluorouridine; 2-(thio)uracil; 2,4- (dithio)psuedouracil; 2' methyl, 2'amino, 2'azido, 2'fluoro-guanosine; 2'-Amino-2'-deoxy-UTP; 2'- Azido-2'-deoxy-UTP; 2'-Azido-deoxyuridine TP; 2'-O-methylpseudouridine; 2' deoxy uridine; 2' fluorouridine; 2'-Deoxy-2'-a-aminouridine TP; 2'-Deoxy-2'-a-azidouridine TP; 2- methylpseudouridine; 3 (3 amino-3 carboxypropyl)uracil; 4 (thio)pseudouridine; 4- (thio)pseudouridine; 4-(thio)uracil; 4-thiouracil; 5 (1,3-diazole-1-alkyl)uracil; 5 (2- aminopropyl)uracil; 5 (aminoalkyl)uracil; 5 (dimethylaminoalkyl)uracil; 5 (guanidiniumalkyl)uracil; 5 (methoxycarbonylmethyl)-2-(thio)uracil; 5 (methoxycarbonyl-methyl)uracil; 5 (methyl) 2 (thio)uracil; 5 (methyl) 2,4 (dithio)uracil; 5 (methyl) 4 (thio)uracil; 5 (methylaminomethyl)-2 (thio)uracil; 5 (methylaminomethyl)-2,4 (dithio)uracil; 5 (methylaminomethyl)-4 (thio)uracil; 5 (propynyl)uracil; 5 (trifluoromethyl)uracil; 5-(2-aminopropyl)uracil; 5-(alkyl)-2-(thio)pseudouridine; 5-(alkyl)-2,4 (dithio)pseudouridine; 5-(alkyl)-4 (thio)pseudouridine; 5-(alkyl)pseudouridine; 5- (alkyl)uracil; 5-(alkynyl)uracil; 5-(allylamino)uracil; 5-(cyanoalkyl)uracil; 5- (dialkylaminoalkyl)uracil; 5-(dimethylaminoalkyl)uracil; 5-(guanidiniumalkyl)uracil; 5-(halo)uracil; 5-(1,3-diazole-1-alkyl)uracil; 5-(methoxy)uracil; 5-(methoxycarbonylmethyl)-2-(thio)uracil; 5- (methoxycarbonyl-methyl)uracil; 5-(methyl) 2(thio)uracil; 5-(methyl) 2,4 (dithio)uracil; 5-(methyl) 4 (thio)uracil; 5-(methyl)-2-(thio)pseudouridine; 5-(methyl)-2,4 (dithio)pseudouridine; 5-(methyl)-4 (thio)pseudouridine; 5-(methyl)pseudouridine; 5-(methylaminomethyl)-2 (thio)uracil; 5- (methylaminomethyl)-2,4(dithio)uracil; 5-(methylaminomethyl)-4-(thio)uracil; 5-(propynyl)uracil; 5- Docket No: 70330WO01 (trifluoromethyl)uracil; 5-aminoallyl-uridine; 5-bromo-uridine; 5-iodo-uridine; 5-uracil; 6 (azo)uracil; 6-(azo)uracil; 6-aza-uridine; allyamino-uracil; aza uracil; deaza uracil; N3 (methyl)uracil; Pseudo- UTP-1-2-ethanoic acid; Pseudouridine; 4-Thio-pseudo-UTP; 1-carboxymethyl-pseudouridine; 1- methyl-1-deaza-pseudouridine; 1-propynyl-uridine; 1-taurinomethyl-1-methyl-uridine; 1- taurinomethyl-4-thio-uridine; 1-taurinomethyl-pseudouridine; 2-methoxy-4-thio-pseudouridine; 2- thio-1-methyl-1-deaza-pseudouridine; 2-thio-1-methyl-pseudouridine; 2-thio-5-aza-uridine; 2-thio- dihydropseudouridine; 2-thio-dihydrouridine; 2-thio-pseudouridine; 4-methoxy-2-thio-pseudouridine; 4-methoxy-pseudouridine; 4-thio-1-methyl-pseudouridine; 4-thio-pseudouridine; 5-aza-uridine; Dihydropseudouridine; (.+-.)1-(2-Hydroxypropyl)pseudouridine TP; (2R)-1-(2- Hydroxypropyl)pseudouridine TP; (2S)-1-(2-Hydroxypropyl)pseudouridine TP; (E)-5-(2-Bromo- vinyl)ara-uridine TP; (E)-5-(2-Bromo-vinyl)uridine TP; (Z)-5-(2-Bromo-vinyl)ara-uridine TP; (Z)-5- (2-Bromo-vinyl)uridine TP; 1-(2,2,2-Trifluoroethyl)-pseudo-UTP; 1-(2,2,3,3,3- Pentafluoropropyl)pseudouridine TP; 1-(2,2-Diethoxyethyl)pseudouridine TP; 1-(2,4,6- Trimethylbenzyl)pseudouridine TP; 1-(2,4,6-Trimethyl-benzyl)pseudo-UTP; 1-(2,4,6-Trimethyl- phenyl)pseudo-UTP; 1-(2-Amino-2-carboxyethyl)pseudo-UTP; 1-(2-Amino-ethyl)pseudo-UTP; 1-(2- Hydroxyethyl)pseudouridine TP; 1-(2-Methoxyethyl)pseudouridine TP; 1-(3,4-Bis- trifluoromethoxybenzyl)pseudouridine TP; 1-(3,4-Dimethoxybenzyl)pseudouridine TP; 1-(3-Amino- 3-carboxypropyl)pseudo-UTP; 1-(3-Amino-propyl)pseudo-UTP; 1-(3-Cyclopropyl-prop-2- ynyl)pseudouridine TP; 1-(4-Amino-4-carboxybutyl)pseudo-UTP; 1-(4-Amino-benzyl)pseudo-UTP; 1-(4-Amino-butyl)pseudo-UTP; 1-(4-Amino-phenyl)pseudo-UTP; 1-(4-Azidobenzyl)pseudouridine TP; 1-(4-Bromobenzyl)pseudouridine TP; 1-(4-Chlorobenzyl)pseudouridine TP; 1-(4- Fluorobenzyl)pseudouridine TP; 1-(4-Iodobenzyl)pseudouridine TP; 1-(4- Methanesulfonylbenzyl)pseudouridine TP; 1-(4-Methoxybenzyl)pseudouridine TP; 1-(4-Methoxy- benzyl)pseudo-UTP; 1-(4-Methoxy-phenyl)pseudo-UTP; 1-(4-Methylbenzyl)pseudouridine TP; 1-(4- Methyl-benzyl)pseudo-UTP; 1-(4-Nitrobenzyl)pseudouridine TP; 1-(4-Nitro-benzyl)pseudo-UTP; 1- (4-Nitro-phenyl)pseudo-UTP; 1-(4-Thiomethoxybenzyl)pseudouridine TP; 1-(4- Trifluoromethoxybenzyl)pseudouridine TP; 1-(4-Trifluoromethylbenzyl)pseudouridine TP; 1-(5- Amino-pentyl)pseudo-UTP; 1-(6-Amino-hexyl)pseudo-UTP; 1,6-Dimethyl-pseudo-UTP; 1-[3-(2-{2- [2-(2-Aminoethoxy)-ethoxy]-ethoxy}-ethoxy)-propionyl]pseudouri- dine TP; 1-{3-[2-(2- Aminoethoxy)-ethoxy]-propionyl} pseudouridine TP; 1-Acetylpseudouridine TP; I-Alkyl-6-(1- propynyl)-pseudo-UTP; 1-Alkyl-6-(2-propynyl)-pseudo-UTP; 1-Alkyl-6-allyl-pseudo-UTP; 1-Alkyl- 6-ethynyl-pseudo-UTP; 1-Alkyl-6-homoallyl-pseudo-UTP; 1-Alkyl-6-vinyl-pseudo-UTP; 1- Allylpseudouridine TP; 1-Aminomethyl-pseudo-UTP; 1-Benzoylpseudouridine TP; 1- Benzyloxymethylpseudouridine TP; 1-Benzyl-pseudo-UTP; 1-Biotinyl-PEG2-pseudouridine TP; 1- Biotinylpseudouridine TP; 1-Butyl-pseudo-UTP; 1-Cyanomethylpseudouridine TP; 1- Docket No: 70330WO01 Cyclobutylmethyl-pseudo-UTP; 1-Cyclobutyl-pseudo-UTP; 1-Cycloheptylmethyl-pseudo-UTP; 1- Cycloheptyl-pseudo-UTP; 1-Cyclohexylmethyl-pseudo-UTP; 1-Cyclohexyl-pseudo-UTP; 1- Cyclooctylmethyl-pseudo-UTP; 1-Cyclooctyl-pseudo-UTP; 1-Cyclopentylmethyl-pseudo-UTP; 1- Cyclopentyl-pseudo-UTP; 1-Cyclopropylmethyl-pseudo-UTP; 1-Cyclopropyl-pseudo-UTP; 1-Ethyl- pseudo-UTP; 1-Hexyl-pseudo-UTP; 1-Homoallylpseudouridine TP; 1-Hydroxymethylpseudouridine TP; 1-iso-propyl-pseudo-UTP; 1-Me-2-thio-pseudo-UTP; 1-Me-4-thio-pseudo-UTP; 1-Me-alpha- thio-pseudo-UTP; 1-Methanesulfonylmethylpseudouridine TP; 1-Methoxymethylpseudouridine TP; 1-Methyl-6-(2,2,2-Trifluoroethyl)pseudo-UTP; 1-Methyl-6-(4-morpholino)-pseudo-UTP; 1-Methyl- 6-(4-thiomorpholino)-pseudo-UTP; 1-Methyl-6-(substituted phenyl)pseudo-UTP; 1-Methyl-6-amino- pseudo-UTP; 1-Methyl-6-azido-pseudo-UTP; 1-Methyl-6-bromo-pseudo-UTP; 1-Methyl-6-butyl- pseudo-UTP; 1-Methyl-6-chloro-pseudo-UTP; 1-Methyl-6-cyano-pseudo-UTP; 1-Methyl-6- dimethylamino-pseudo-UTP; 1-Methyl-6-ethoxy-pseudo-UTP; 1-Methyl-6-ethylcarboxylate-pseudo- UTP; 1-Methyl-6-ethyl-pseudo-UTP; 1-Methyl-6-fluoro-pseudo-UTP; 1-Methyl-6-formyl-pseudo- UTP; 1-Methyl-6-hydroxyamino-pseudo-UTP; 1-Methyl-6-hydroxy-pseudo-UTP; 1-Methyl-6-iodo- pseudo-UTP; 1-Methyl-6-iso-propyl-pseudo-UTP; 1-Methyl-6-methoxy-pseudo-UTP; 1-Methyl-6- methylamino-pseudo-UTP; 1-Methyl-6-phenyl-pseudo-UTP; 1-Methyl-6-propyl-pseudo-UTP; 1- Methyl-6-tert-butyl-pseudo-UTP; 1-Methyl-6-trifluoromethoxy-pseudo-UTP; 1-Methyl-6- trifluoromethyl-pseudo-UTP; 1-Morpholinomethylpseudouridine TP; 1-Pentyl-pseudo-UTP; 1- Phenyl-pseudo-UTP; 1-Pivaloylpseudouridine TP; 1-Propargylpseudouridine TP; 1-Propyl-pseudo- UTP; 1-propynyl-pseudouridine; 1-p-tolyl-pseudo-UTP; 1-tert-Butyl-pseudo-UTP; 1- Thiomethoxymethylpseudouridine TP; 1-Thiomorpholinomethylpseudouridine TP; 1- Trifluoroacetylpseudouridine TP; 1-Trifluoromethyl-pseudo-UTP; 1-Vinylpseudouridine TP; 2,2'- anhydro-uridine TP; 2'-bromo-deoxyuridine TP; 2'-F-5-Methyl-2'-deoxy-UTP; 2'-OMe-5-Me-UTP; 2'- OMe-pseudo-UTP; 2'-a-Ethynyluridine TP; 2'-a-Trifluoromethyluridine TP; 2'-b-Ethynyluridine TP; 2'-b-Trifluoromethyluridine TP; 2'-Deoxy-2',2'-difluorouridine TP; 2'-Deoxy-2'-a-mercaptouridine TP; 2'-Deoxy-2'-a-thiomethoxyuridine TP; 2'-Deoxy-2'-b-aminouridine TP; 2'-Deoxy-2'-b- azidouridine TP; 2'-Deoxy-2'-b-bromouridine TP; 2'-Deoxy-2'-b-chlorouridine TP; 2'-Deoxy-2'-b- fluorouridine TP; 2'-Deoxy-2'-b-iodouridine TP; 2'-Deoxy-2'-b-mercaptouridine TP; 2'-Deoxy-2'-b- thiomethoxyuridine TP; 2-methoxy-4-thio-uridine; 2-methoxyuridine; 2'-O-Methyl-5-(1- propynyl)uridine TP; 3-Alkyl-pseudo-UTP; 4'-Azidouridine TP; 4'-Carbocyclic uridine TP; 4'- Ethynyluridine TP; 5-(1-Propynyl)ara-uridine TP; 5-(2-Furanyl)uridine TP; 5-Cyanouridine TP; 5- Dimethylaminouridine TP; 5'-Homo-uridine TP; 5-iodo-2'-fluoro-deoxyuridine TP; 5- Phenylethynyluridine TP; 5-Trideuteromethyl-6-deuterouridine TP; 5-Trifluoromethyl-Uridine TP; 5- Vinylarauridine TP; 6-(2,2,2-Trifluoroethyl)-pseudo-UTP; 6-(4-Morpholino)-pseudo-UTP; 6-(4- Thiomorpholino)-pseudo-UTP; 6-(Substituted-Phenyl)-pseudo-UTP; 6-Amino-pseudo-UTP; 6- Docket No: 70330WO01 Azido-pseudo-UTP; 6-Bromo-pseudo-UTP; 6-Butyl-pseudo-UTP; 6-Chloro-pseudo-UTP; 6-Cyano- pseudo-UTP; 6-Dimethylamino-pseudo-UTP; 6-Ethoxy-pseudo-UTP; 6-Ethylcarboxylate-pseudo- UTP; 6-Ethyl-pseudo-UTP; 6-Fluoro-pseudo-UTP; 6-Formyl-pseudo-UTP; 6-Hydroxyamino-pseudo- UTP; 6-Hydroxy-pseudo-UTP; 6-Iodo-pseudo-UTP; 6-iso-Propyl-pseudo-UTP; 6-Methoxy-pseudo- UTP; 6-Methylamino-pseudo-UTP; 6-Methyl-pseudo-UTP; 6-Phenyl-pseudo-UTP; 6-Phenyl-pseudo- UTP; 6-Propyl-pseudo-UTP; 6-tert-Butyl-pseudo-UTP; 6-Trifluoromethoxy-pseudo-UTP; 6- Trifluoromethyl-pseudo-UTP; Alpha-thio-pseudo-UTP; Pseudouridine 1-(4-methylbenzenesulfonic acid) TP; Pseudouridine 1-(4-methylbenzoic acid) TP; Pseudouridine TP 1-[3-(2-ethoxy)]propionic acid; Pseudouridine TP 1-[3-{2-(2-[2-(2-ethoxy)-ethoxy]-ethoxy)-ethoxy}]propionic acid; Pseudouridine TP 1-[3-{2-(2-[2-{2-(2-ethoxy)-ethoxy)-ethoxy}-ethoxy]-ethoxy}]propionic acid; Pseudouridine TP 1-[3-{2-(2-[2-ethoxy]-ethoxy)-ethoxy}]propionic acid; Pseudouridine TP 1-[3-{2- (2-ethoxy)-ethoxy}]propionic acid; Pseudouridine TP 1-methylphosphonic acid; Pseudouridine TP 1- methylphosphonic acid diethyl ester; Pseudo-UTP-N1-3-propionic acid; Pseudo-UTP-N1-4-butanoic acid; Pseudo-UTP-N1-5-pentanoic acid; Pseudo-UTP-N1-6-hexanoic acid; Pseudo-UTP-N1-7- heptanoic acid; Pseudo-UTP-N1-methyl-p-benzoic acid; Pseudo-UTP-N1-p-benzoic acid; Wybutosine; Hydroxywybutosine; Isowyosine; Peroxywybutosine; undermodified hydroxywybutosine; 4-demethylwyosine; 2,6-(diamino)purine; 1-(aza)-2-(thio)-3-(aza)-phenoxazin- 1-yl: 1,3-(diaza)-2-(oxo)-phenthiazin-1-yl; 1,3-(diaza)-2-(oxo)-phenoxazin-1-yl; 1,3,5-(triaza)-2,6- (dioxa)-naphthalene; 2 (amino)purine; 2,4,5-(trimethyl)phenyl; 2' methyl, 2'amino, 2'azido, 2'fluoro- cytidine; 2' methyl, 2'amino, 2'azido, 2'fluoro-adenine; 2'methyl, 2'amino, 2'azido, 2'fluoro-uridine; 2'- amino-2'-deoxyribose; 2-amino-6-Chloro-purine; 2-aza-inosinyl; 2'-azido-2'-deoxyribose; 2'fluoro-2'- deoxyribose; 2'-fluoro-modified bases; 2'-O-methyl-ribose; 2-oxo-7-aminopyridopyrimidin-3-yl; 2- oxo-pyridopyrimidine-3-yl; 2-pyridinone; 3 nitropyrrole; 3-(methyl)-7-(propynyl)isocarbostyrilyl; 3- (methyl)isocarbostyrilyl; 4-(fluoro)-6-(methyl)benzimidazole; 4-(methyl)benzimidazole; 4- (methyl)indolyl; 4,6-(dimethyl)indolyl; 5 nitroindole; 5 substituted pyrimidines; 5- (methyl)isocarbostyrilyl; 5-nitroindole; 6-(aza)pyrimidine; 6-(azo)thymine; 6-(methyl)-7-(aza)indolyl; 6-chloro-purine; 6-phenyl-pyrrolo-pyrimidin-2-on-3-yl; 7-(aminoalkylhydroxy)-1-(aza)-2-(thio)-3- (aza)-phenthiazin-1-yl; 7-(aminoalkylhydroxy)-1-(aza)-2-(thio)-3-(aza)-phenoxazin-1-yl; 7- (aminoalkylhydroxy)-1,3-(diaza)-2-(oxo)-phenoxazin-1-yl; 7-(aminoalkylhydroxy)-1,3-(diaza)-2- (oxo)-phenthiazin-1-yl; 7-(aminoalkylhydroxy)-1,3-(diaza)-2-(oxo)-phenoxazin-1-yl; 7-(aza)indolyl; 7-(guanidiniumalkylhydroxy)-1-(aza)-2-(thio)-3-(aza)-phenoxazinl-yl; 7-(guanidiniumalkylhydroxy)- 1-(aza)-2-(thio)-3-(aza)-phenthiazin-1-yl; 7-(guanidiniumalkylhydroxy)-1-(aza)-2-(thio)-3-(aza)- phenoxazin-1-yl; 7-(guanidiniumalkylhydroxy)-1,3-(diaza)-2-(oxo)-phenoxazin-1-yl; 7- (guanidiniumalkyl-hydroxy)-1,3-(diaza)-2-(oxo)-phenthiazin-1-yl; 7-(guanidiniumalkylhydroxy)-1,3- (diaza)-2-(oxo)-phenoxazin-1-yl; 7-(propynyl)isocarbostyrilyl; 7-(propynyl)isocarbostyrilyl, Docket No: 70330WO01 propynyl-7-(aza)indolyl; 7-deaza-inosinyl; 7-substituted 1-(aza)-2-(thio)-3-(aza)-phenoxazin-1-yl; 7- substituted 1,3-(diaza)-2-(oxo)-phenoxazin-1-yl; 9-(methyl)-imidizopyridinyl; Aminoindolyl; Anthracenyl; bis-ortho-(aminoalkylhydroxy)-6-phenyl-pyrrolo-pyrimidin-2-on-3-yl; bis-ortho- substituted-6-phenyl-pyrrolo-pyrimidin-2-on-3-yl; Difluorotolyl; Hypoxanthine; Imidizopyridinyl; Inosinyl; Isocarbostyrilyl; Isoguanisine; N2-substituted purines; N6-methyl-2-amino-purine; N6- substituted purines; N-alkylated derivative; Napthalenyl; Nitrobenzimidazolyl; Nitroimidazolyl; Nitroindazolyl; Nitropyrazolyl; Nubularine; O6-substituted purines; O-alkylated derivative; ortho- (aminoalkylhydroxy)-6-phenyl-pyrrolo-pyrimidin-2-on-3-yl; ortho-substituted-6-phenyl-pyrrolo- pyrimidin-2-on-3-yl; Oxoformycin TP; para-(aminoalkylhydroxy)-6-phenyl-pyrrolo-pyrimidin-2-on- 3-yl; para-substituted-6-phenyl-pyrrolo-pyrimidin-2-on-3-yl; Pentacenyl; Phenanthracenyl; Phenyl; propynyl-7-(aza)indolyl; Pyrenyl; pyridopyrimidin-3-yl; pyridopyrimidin-3-yl, 2-oxo-7-amino- pyridopyrimidin-3-yl; pyrrolo-pyrimidin-2-on-3-yl; Pyrrolopyrimidinyl; Pyrrolopyrizinyl; Stilbenzyl; substituted 1,2,4-triazoles; Tetracenyl; Tubercidine; Xanthine; Xanthosine-5'-TP; 2-thio-zebularine; 5- aza-2-thio-zebularine; 7-deaza-2-amino-purine; pyridin-4-one ribonucleoside; 2-Amino-riboside-TP; Formycin A TP; Formycin B TP; Pyrrolosine TP; 2'-OH-ara-adenosine TP; 2'-OH-ara-cytidine TP; 2'- OH-ara-uridine TP; 2'-OH-ara-guanosine TP; 5-(2-carbomethoxyvinyl)uridine TP; or N6-(19-Amino- pentaoxanonadecyl)adenosine TP. In some embodiments, the percentage of standard As substituted with A-substitutable modified nucleotide (e.g. those above) is at least: 0.1%, 0.5%, 0.8%, 1%, 2%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or at least 99.9%, or 100%. In some embodiments, the percentage of standard As substituted with m6A may be 0.1-5%, in particular 0.5- 2%, in particular 0.8-1.2%, such as about 1% (or 1%); in these embodiments the RNA may be circular RNA. Low substitution levels with m6A (e.g.1%) have been shown in inhibit innate immune activation [16]. In some embodiments, the percentage of standard Cs substituted with cytosine-substitutable modified nucleotide (e.g. those above) is at least: 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or at least 99.9%, or 100%. In some embodiments, the percentage of standard Gs substituted with G-substitutable modified nucleotide (e.g. those above) is at least: 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or at least 99.9%, or 100%. In preferred embodiments, the percentage of standard Us substituted with U-substitutable modified nucleotide (e.g. those above) is at least: 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or at least 99.9%, or preferably 100%; more preferably with 1mΨ and/or Ψ (even more preferably 1mΨ) . In a preferred embodiment, the one or more modified ribonucleotides detailed above is, or comprise, 1mΨ and/or Ψ, more preferably 1mΨ. In such embodiments, the RNA may comprise 1mΨ and/or Ψ, Docket No: 70330WO01 and neither standard U ribonucleotides nor other modified U ribonucleotides (i.e. there are no standard U nucleotides, nor modified U ribonucleotides other than 1mΨ and/or Ψ, in the RNA; i.e. 100% U substitution). In particular, the RNA may comprise 1mΨ and/or Ψ, and neither standard U ribonucleotides nor other modified ribonucleotides (i.e. there are no standard U nucleotides, nor modified ribonucleotides of any type - A, C, G or U substitutable - other than 1mΨ and/or Ψ, in the RNA; i.e. 100% U substitution with no other modified nucleotides being allowed). The RNA may comprise Ψ, and neither standard U ribonucleotides nor other modified U ribonucleotides (i.e. 100% U substitution with Ψ). In particular, the RNA may comprise Ψ, and neither standard U ribonucleotides nor other modified ribonucleotides (i.e. 100% U substitution with Ψ with no other modified nucleotides being allowed). More preferably, the RNA comprises 1mΨ, and neither standard U ribonucleotides nor other modified U ribonucleotides (i.e.100% U substitution with 1mΨ). In an even more preferred embodiment, the RNA comprises 1mΨ, and neither standard U ribonucleotides nor other modified ribonucleotides (i.e.100% U substitution with 1mΨ with no other modified nucleotides being allowed). In the embodiments in this paragraph, “[may] comprise[s]... and neither [X]...nor [Y]” may be used interchangeably with the wording “[may] comprise[s]... and does not comprise... [X] and/or [Y] ”. Preferably, the RNA is codon-optimised. In some embodiments, the RNA may be codon optimised for expression in human cells. Codon optimisation refers to the use of specific codons, which, while not altering the sequence of the expressed protein (given genetic code redundancy), may increase translation efficacy and/or half- life of the RNA. Codon optimisation may provide an elevated GC content, relative to non-codon optimised RNA encoding the same protein(s). The GC content (the percentage of all ribonucleotides (or, defined alternatively, all “nitrogenous bases”) in the RNA which are G or C) of the RNA may be at least 10%, such as at least 20%, 30%, 35% or at least 40%, preferably at least 45%, 46%, 47%, 48%, 49%, or at least 50%. The GC content of the RNA may be 10-70%, such as 20-65%, 30-65% or 35-65%, preferably 40-60%, 45-55%, 46-53%, 47-51%, or 48-50%. The GC content of the RNA may be 30-70%, such as 40-70%, 45-70%, 50-70%, or 55-70%. Codon optimisation may provide an elevated C content relative to non-codon optimised RNA encoding the same protein(s). The percentage of C-optimisable codons in the RNA which have been substituted, as a result of codon optimisation, for a codon with greater C content (while encoding the same amino acid) may be least 30%, such as at least 40%, 50%, 55% or at least 60%, preferably at least 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72% or at least 72%; The percentage of C-optimisable codons in the RNA which have been substituted, as a result of codon optimisation, for a codon with greater C content (while encoding the same amino acid) may be 30-80%, such as 40-90%, 45-90%, 50-80%, 55-80% or 60-80%, preferably 65-75%, 66-75%, 67-75%, 68-75%, 69-75%, 70-74%, 71-74% or 72-74%. Docket No: 70330WO01 Generally, the RNA comprises both a 5’ and a 3’ untranslated region (UTR). In some preferred embodiments, the RNA comprises a 5’ and a 3’ UTR selected from: - SEQ ID NO: 18 and 19, respectively, and - SEQ ID NO: 20 and 21, respectively, - RNA sequences at least 70%, 75%, 80%, 85%, 90% 95%, 96%, 97%, 98% or at least 99% identical to SEQ ID NO: 18 or 20, (for the 5’ UTR) and RNA sequences at least 70%, 75%, 80%, 85%, 90% 95%, 96%, 97%, 98%, 99% or at least 99.5% identical to SEQ ID NO: 19 or 21, (for the 3’ UTR) (preferably, the pairing of 5’ and 3’ UTRs having such identity to SEQ ID NO: 18 and 19, or SEQ ID NO: 20 and 21, respectively); Both the 3’ and 5’ UTR may influence expression of the RSV-F protein of the present disclosure through a variety of mechanisms. Without wishing to be found by this theory, the 5’ UTR may affect the expression of at least the RSV-F protein of the present disclosure e.g. via pre-initiation complex regulation, closed-loop regulation, upstream open reading frame regulations (i.e. reinitiation), provision of internal ribosome entry sites, and provision of microRNA binding sites. Without wishing to be found by this theory, the 3’ UTR may affect the expression of at least the RSV-F protein of the present disclosure e.g. via providing regulation regions that post-transcriptionally influence expression; e.g. influencing translation efficiency, localisation of the RNA, stability of the RNA, polyadenylation, and circularization of the RNA. In one specific embodiment, the RNA is circular RNA. In a preferred embodiment, the RNA fulfils at least two, at least three, at least four, or at least five of the following criteria (for example, (a), (b), (d) and (f); (a), (b), (c), (d) and (f); or (a), (b), (d), (e) and (f): (a) is non-self-replicating; (b) is single stranded; (c) comprises a 5’ cap, which is a 7-methylguanosine linked 5’-to-5’ to the 5’ first ribonucleotide by a triphosphate bridge, and wherein the first 5’ ribonucleotide comprises a 2’-methylated ribose (2’-O-Me); (d) comprises a 3’poly-A tail; (e) comprises 1mΨ, and neither standard U ribonucleotides nor other modified ribonucleotides; Docket No: 70330WO01 (f) comprises a 5’ and a 3’ UTR; preferably a 5’ and a 3’ UTR selected from SEQ ID NO: 18 and 19 respectively, and SEQ ID NO: 20 and 21 respectively; or RNA sequences at least 70%, 75%, 80%, 85%, 90% 95%, 96%, 97%, 98% or at least 99% identical to SEQ ID NO: 18 or 20, (for the 5’ UTR) and RNA sequences at least 70%, 75%, 80%, 85%, 90% 95%, 96%, 97%, 98%, 99% or at least 99.5% identical to SEQ ID NO: 19 or 21, (for the 3’ UTR) (preferably, the pairing of 5’ and 3’ UTRs having such identity to SEQ ID NO: 18 and 19, or SEQ ID NO: 20 and 21, respectively). In another preferred embodiment, the RNA fulfils all of criteria (a) – (f), above. Generally, the RNA will comprise, in the 5’ to 3’ direction: 5’ Cap, 5’ UTR, open reading frame encoding at least an RSV-F protein of the present disclosure, 3’UTR, and 3’ poly-A tail (in particular, the 5’ Caps; 5’ UTRs, 3’UTRs and 3’ poly-A tails as detailed above throughout this subsection). In preferred embodiments, the RNA comprises or consists of (i) SEQ ID NO: 4; or (ii) an RNA sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or at least 99.9% identical thereto; preferably wherein the RNA encodes an RSV-F protein comprising a C residue at position 103, a C residue at position 148, an I residue at position 190 and an S residue at position 486. In preferred embodiments, the RNA comprises an open reading frame (ORF) comprising or consisting of the sequence of: (i) positions 32-1753 of SEQ ID NO: 4; or (ii) an RNA sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or at least 99.9% identical thereto; preferably wherein the RNA encodes an RSV-F protein comprising a C residue at position 103, a C residue at position 148, an I residue at position 190 and an S residue at position 486. The present disclosure also provides, in a further independent aspect, a DNA construct (preferably a DNA plasmid) encoding an RNA sequence of the present disclosure. The present disclosure also provides, in a further independent aspect, a vector comprising one or more RNAs of the present disclosure. The present disclosure also provides, in a further independent aspect, a vector comprising a DNA construct encoding one or more RNAs of the present disclosure. The present disclosure also provides, in a further independent aspect, an RNA comprising or consisting of (i) SEQ ID NO: 4; or (ii) an RNA sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or at least 99.9% identical thereto. Said RNA / RNA sequence may have any of the features detailed throughout this subsection Docket No: 70330WO01 entitled “General features of RNA of the present disclosure”. The present disclosure also provides, in a further independent aspect, a DNA construct (preferably a DNA plasmid) encoding an RNA sequence comprising or consisting of SEQ ID NO: 4, or any of the foregoing sequences having sequence identity to SEQ ID NO: 4. The present disclosure also provides, in a further independent aspect, an RNA comprising an open reading frame (ORF) comprising or consisting of the sequence of: (i) positions 32-1753 of SEQ ID NO: 4; or (ii) an RNA sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or at least 99.9% identical thereto. Said RNA / RNA sequence may have any of the features detailed throughout this subsection entitled “General features of RNA of the present disclosure”. The present disclosure also provides, in a further independent aspect, a DNA construct (preferably a DNA plasmid) encoding an RNA sequence comprising an ORF comprising or consisting of the sequence of: positions 32-1753 of SEQ ID NO: 4, or any of the foregoing sequences having sequence identity to SEQ ID NO: 4. The RNA may encode an RSV-F protein of the present disclosure only (i.e. the RNA encodes a single protein). Alternatively, the RNA may encode multiple proteins, of which one is the RSV-F protein of the present disclosure. In some embodiments, the RNA encodes at least (i) an RSV-F protein of the present disclosure; and (ii) at least one further protein. The at least one further protein may be a nanoparticle, e.g. a ferritin nanoparticle (e.g. which is encoded, along with the RSV-F protein of the present disclosure, by a single open reading frame, resulting in expression of a single polypeptide/protein). In preferred embodiments, the at least one further protein is an antigen; and as such may comprise, or may be, a viral, bacterial, fungal, parasitic, tumour, or allergenic (i.e. from, or derived from, an allergen) antigen; typically encoded by a separate open reading frame to the RSV-F protein of the invention. The at least one further protein will typically be a pathogen antigen. The at least one further protein will typically be an antigen that is a surface polypeptide e.g. a spike glycoprotein, a haemagglutinin, an adhesin or an envelope glycoprotein. In a particular embodiment, the at least one further protein is an antigen from, or derived from, a virus, in particular a virus causing respiratory disease, in particular a seasonal virus causing respiratory disease. In embodiments wherein the at least one further protein is an antigen from, or derived from, a virus, examples of such viruses include: Coronavirus, Orthomyxovirus, Pneumoviridae, Paramyxoviridae, Poxviridae, Picornavirus, Bunyavirus, Heparnavirus, Filovirus, Togavirus, Flavivirus, Pestivirus, Hepadnavirus, Rhabdovirus, Caliciviridae, Retrovirus, Reovirus, Parvovirus, Herpesvirus, Papovaviruses and Adenovirus. In a preferred embodiment, the at least one further protein detailed above is a further Pneumoviridae protein (in particular a Pneumoviridae antigen). Useful further Pneumoviridae proteins (in particular, Docket No: 70330WO01 antigens) can be from an Orthopneumovirus or Metapneumovirus, in particular human RSV or human Metapneumovirus (hMPV). Useful further hMPV antigens include e.g. the F, N, P, M, M2-1, and M2 antigens (in particular, the F antigen). Such hMPV proteins (in particular, antigens) may be from, or derived from, the A or B subtype. In a preferred embodiment, the RNA encodes an RSV-F protein of the present disclosure in addition to an hMPV antigen (in particular, the F antigen). In such embodiments, a preferred patient group (in which the RNA may be used in therapy, in particular vaccination) is infants (see section entitled Medical uses and methods of treatment, below). Useful further human RSV antigens include e.g. the G, M1, M2-1, M2-2, P, L, N, NS1, NS2 and SH antigens, in addition to further RSV-F antigens, i.e. of distinct amino acid sequence to the RSV-F protein of the present disclosure encoded by the RNA. Such further human RSV proteins (in particular, antigens) may be from, or derived from, the A or B subtype. In a preferred embodiment, the at least one further protein detailed above is a Coronavirus antigen. Useful Coronavirus antigens can be from a SARS coronavirus, in particular SARS-CoV2. Useful Coronavirus antigens (preferably SARS-CoV2 antigens) include the spike, M, E, HE, Nuclocapsid, Plpro and 3CLPro proteins, in particular spike protein. Preferably, the Coronavirus antigen is a SARS- CoV2 spike protein. Said SARS-CoV2 spike protein may be from any variant, e.g. Omicron (such as Omicron BA.1, BA.2, BA3, BA.4 or BA.5), Alpha, Epsilon, Eta, Theta, Kappa, Iota, Zeta, Mu, Lambda, Beta, Gamma, or Delta. Preferably, said SARS-CoV2 spike protein includes one or more mutations relative to the wild-type protein, in particular one or more (e.g. two) mutations to proline resides. Said one or more mutations may be introduced to stabilise said SARS-CoV2 spike protein in its pre-fusion conformation. A preferred patient group (in which the RNA may be used in therapy, in particular vaccination) is older adults (see section entitled Medical uses and methods of treatment, below). In another preferred embodiment, the at least one further protein detailed above is an Orthomyxovirus antigen. Useful Orthomyxovirus antigens can be from an influenza A, B or C virus. Useful Orthomyxovirus antigens (in particular influenza A, B or C virus antigens) include the haemagglutinin, neuraminidase and matrix M2 proteins, in particular haemagglutinin. Preferably, the Orthomyxovirus antigen is an influenza A virus haemagglutinin. Said influenza A virus hemagglutinin may be from any subtype e.g. H1, H2, H3, H4, H5, H6, H7, H8, H9, H10, H11, H12, H13, H14, H15 or H16. In such embodiments, the RNA may encode (i) an RSV-F protein of the present disclosure, (ii) a Coronavirus antigen, e.g. as detailed above, and (iii) an Orthomyxovirus antigen, e.g. as detailed above. A preferred patient group (in which the RNA may be used in therapy, in particular vaccination) is older adults (see section entitled Medical uses and methods of treatment, below). Docket No: 70330WO01 RNA sequence alignments may be performed, for example, visually, or by any well-known algorithm; e.g. using an NCBI BLAST algorithm such as “megablast”, e.g. on default settings (available at e.g. https://blast.ncbi.nlm.nih.gov/Blast.cgi?PROGRAM=blastn&BLAST_SPEC=GeoBlast&PAGE_TY PE=BlastSearch); or e.g. using the “Muscle” algorithm (see, e.g. [17], [18]), e.g. on default settings; with the Muscle algorithm being preferred. Corresponding ribonucleotide positions are easily identifiable to the skilled person, and can be identified by aligning the ribonucleotide sequences using any well-known method (such as visual or algorithm, e.g. as detailed above). The RNA can conveniently be prepared by in vitro transcription (IVT). IVT can use a (DNA) template created and propagated in plasmid form in bacteria, or created synthetically (for example by gene synthesis and/or polymerase chain-reaction (PCR) engineering methods). For instance, a DNA- dependent RNA polymerase (such as the bacteriophage T7, T3 or SP6 RNA polymerases) can be used to transcribe the replicating RNA from a DNA template. Appropriate capping and poly-A addition reactions can be used as required (although the poly-A tail is usually encoded within the DNA template). A plurality of RNA molecules of the present disclosure is, in particular, provided in purified or substantially purified form; that is, substantially free from other nucleic acids or RNAs (e.g. free or substantially free from naturally-occurring nucleic acids or RNAs, such as further nucleic acids or RNAs expressed by a host cell). Said plurality of RNA molecules is generally at least 50% pure (by weight), such as at least 60%, 70%, 80%, 90%, or 95% pure (by weight). The RNA may be delivered naked, or preferably in conjunction with a carrier (e.g. as detailed in the section entitled Carriers, below). Carriers comprising an RNA of the present disclosure RNA molecules by themselves and unprotected, may be degraded by the subject’s nucleases and may require a carrier to facilitate target cell entry. Accordingly, the present disclosure also provides a carrier comprising an RNA molecule encoding an RSV-F protein of the present disclosure. The carrier may be lipid-based (e.g. a lipid nanoparticle or cationic nanoemulsion), polymer-based (e.g. comprising polyamines, dendrimers and/or copolymers), peptide or protein-based (e.g. comprising protamine, a cationic cell-penetrating peptide, and/or an anionic peptide conjugated to a positively charged polymer), cell-based (e.g. antigen presenting cells, such as dendritic cells loaded with the RNA), or virus-based (e.g. viral replicon particles). In particular embodiments, the carrier is non-virion, i.e. free or substantially free of viral capsid. Docket No: 70330WO01 In particular, lipid-based carriers provide a means to protect the RNA, e.g. through encapsulation, and deliver it to target cells for protein expression. In certain embodiments, the lipid-based carrier is, or comprises, a cationic nano-emulsion (“CNE”). CNEs and methods for their preparation are described in, for example, [19]. With a CNE, the RNA which encodes the RSV-F protein of the present disclosure is complexed with a CNE particle, in particular comprising an oil core and a cationic lipid. The cationic lipid can interact with the negatively charged molecule, thereby anchoring the molecule to the emulsion particles. In a particular embodiment, a lipid-based carrier is a lipid inorganic nanoparticle (“LION”). LNPs In a preferred embodiment, RNA molecules are encapsulated in a lipid nanoparticle (LNP). Thus, in a preferred embodiment, the present disclosure also provides an LNP encapsulating an RNA molecule which encodes an RSV-F protein of the present disclosure. A plurality of such LNPs will be part of a composition (e.g. a pharmaceutical composition as detailed in the section entitled Pharmaceutical compositions below) comprising free and/or encapsulated RNA, and in some embodiments the LNPs encapsulate at least: 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97.0%, 97.1%, 97.2%, 97.3%, 97.4%, 97.5%, 97.6%, 97.7%, 97.8%, 97.9%, 98.0%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99.0%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or at least 100% of the total number of RNA molecules in the composition. At least 80% of the LNPs in the composition may be 20-200 nm, 40- 190 nm, 60-180 nm or, in particular, 80-160 nm in diameter. In a particular embodiment, substantially all, or all, LNPs in the composition are 20-200 nm, 40-190 nm, 60-180 nm or, in particular, 80-160 nm in diameter. The LNP can comprise multilamellar vesicles (MLV), small uniflagellar vesicles (SUV), or large unilamellar vesicles (LUV). The amount of RNA per LNP can vary, and the number of individual RNA molecules per LNP can depend on the characteristics of the particle being used. For RNA molecules, in general, an LNP may include 1-500 RNA molecules, e.g. <200, <100, <50, <20, <10, <5, or 1-4. Generally, an LNP includes fewer than 10 different species of RNA e.g. fewer than 5, 4, 3, or 2 different species. Preferably the LNP includes a single RNA species (i.e. all RNA molecules in the particle have the same sequence). LNPs according to the present disclosure may be formed from a single lipid (e.g. a cationic lipid) or, in particular, from a mixture of lipids. In particular, the mixture comprises various classes of lipids, such as: (a) a mixture of cationic lipids and sterols, Docket No: 70330WO01 (b) a mixture of cationic lipids and neutral lipids, (c) a mixture of cationic lipids and polymer-conjugated lipids, (d) a mixture of cationic lipids, sterols and polymer-conjugated lipids, or (e) a mixture of cationic lipids, neutral lipids and polymer-conjugated lipids; or preferably: (f) a mixture of cationic lipids, sterols and neutral lipids; or more preferably: (g) a mixture of cationic lipids, neutral lipids, sterols and polymer-conjugated lipids. Further classes of lipids, such as anionic lipids, may also be present in a mixture of lipids. The cationic lipid may have a pKa of 5.0-10.0, 5.0-9.0, 5.0-8.5, preferably 5.0-8.0, 5.0-7.9, or 5.0-7.8, 5.0-7.7, or more preferably 5.0-7.6. The pKa of the cationic lipid is distinct to the pKa of the LNP as a whole (sometimes called “apparent pKa”). pKa may be determined via any well-known method, such as via a toluene nitrosulphonic acid (TNS) fluorescence assay or acid base titration; preferably a TNS fluorescence assay; more preferably performed according to Example 3. The cationic lipid preferably comprises a tertiary or quaternary amine group, more preferably a tertiary amine group. Exemplary cationic lipids comprising tertiary amine groups include: 1,2-dilinoleyoxy- 3-(dimethylamino)acetoxypropane (DLin-DAC), 1,2-dilinoleyoxy-3morpholinopropane (DLin-MA), 1,2-dilinoleoyl-3-dimethylaminopropane (DLinDAP), 1,2-dilinoleylthio-3-dimethylaminopropane (DLin-S-DMA), 1-linoleoyl-2-linoleyloxy-3dimethylaminopropane (DLin-2-DMAP), 1,2- dilinoleyloxy-3-trimethylaminopropane chloride salt (DLin-TMA.Cl), 1,2-dilinoleoyl-3- trimethylaminopropane chloride salt (DLin-TAP.Cl), 1,2-dilinoleyloxy-3-(N- methylpiperazino)propane (DLin-MPZ), 3-(N,Ndilinoleylamino)-1,2-propanediol (DLinAP), 3-(N,N- dioleylamino)-1,2-propanediol (DOAP), 1,2-dilinoleyloxo-3-(2-N,N-dimethylamino)ethoxypropane (DLin-EG-DMA), and 2,2-dilinoleyl-4-dimethylaminomethyl[1,3]-dioxolane (DLin-K-DMA), 2,2- dilinoleyl-4-(2-dimethylaminoethyl)[1,3]-dioxolane (DLin-KC2-DMA); dilinoleyl-methyl-4- dimethylaminobutyrate (DLin-MC3-DMA); or MC3 (see, e.g. [20]). In some embodiments, the cationic lipid has the structure of lipid RV28, RV31, RV33, RV37, RV39 RV42, RV44, RV73, RV75, RV81, RV84, RV85, RV86, RV88, RV91, RV92, RV93, RV94, RV95, Docket No: 70330WO01 RV96, RV97, RV99 or RV101, as disclosed in [21]. In a further embodiment, the cationic lipid has the structure:

In a preferred embodiment, the cationic lipid has the structure:

(also referred to as lipid RV39). In another preferred embodiment, the cationic lipid has the structure:

In another preferred embodiment, the cationic lipid has the structure: Docket No: 70330WO01

The lipids in the LNP may comprise (in mole %) 20-80, 25-75, 30-70, or 35-65%, preferably 30-60, 40-55 or 40-50% cationic lipid; such as about 40% (or 40%), about 42% (or 42%), about 44% (or 44%), about 46% (or 46%) or about 48% (or 48%) cationic lipid. The lipids in the LNP may comprise (in mole %) at least 20, 25 or at least 35%, or preferably at least 40% cationic lipid. The lipids in the LNP may comprise (in mole %) no more than 80, 70 or no more than 60% or preferably no more than 50% cationic lipid. The molar ratio of protonatable nitrogen atoms in the LNP’s cationic lipids to phosphates in the RNA (a.k.a “N:P” ratio), may be in the range of (including the endpoints) 1:1-20:1, 2:1-10:1, 3:1-9:1, or 4:1- 8:1; preferably 4.5:1-7.5:1, 4.5:1-6.5:1 or 5.0:1-6.5:1. The polymer-conjugated lipid is preferably a PEGylated lipid. In an LNP, the PEGs of such PEGylated lipids may have a weight average molecular weight of 0.5-11.0 kDa; such as 0.5-8.0, 0.8-8.0, 0.8-7.0, 0.8-6.0, 0.8-5.0, 0.8-4.0, 1.0-4.0 or 1.0-3.5 kDa, preferably 1.0-3.0, 1.2-2.8, 1.4-2.6, 1.5-2.5, 1.6-2.4, or 1.7-2.3 kDa, or more preferably 1.8-2.2, 1.9-2.1, about 2.0 (or 2.0 kDa). Alternatively, in an LNP, the PEGs of such PEGylated lipids may have a number average molecular weight of 0.5-11.0 kDa; such as 0.5-8.0, 0.8-8.0, 0.8-7.0, 0.8-6.0, 0.8-5.0, 0.8-4.0, 1.0-4.0 or 1.0-3.5 kDa, preferably 1.0-3.0, 1.2-2.8, 1.4-2.6, 1.5-2.5, 1.6-2.4, or 1.7-2.3 kDa, or more preferably 1.8-2.2, 1.9-2.1, about 2.0 (or 2.0 kDa). The PEGylated lipid may have the structure: Docket No: 70330WO01 Exemplary PEGylated lipids include 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide and 1,2-dimyristoyl-rac-glycero-3-methoxypolyethylene glycol-2000, 1,2-dimyristoyl-sn-glycero-2- phosphoethanolamine-N-[methoxy(polyethylene glycol)] and 1,2-dimyristoyl-rac-glycerol-3- methoxypolyethylene glycol. Preferably, the PEGylated lipid is 2-[(polyethylene glycol)-2000]-N,N- ditetradecylacetamide or 1,2-dimyristoyl-rac-glycero-3-methoxypolyethylene glycol-2000. The lipids in the LNP may comprise (in mole %) 0.1-8.0, 0.4-7.0, 0.6-6.0, 0.8-4.0 or 0.8-3.5%, preferably 1.0-3.0% polymer-conjugated lipid (preferably PEGylated lipid); such as about 1.0 (or 1.0%), about 1.5% (or 1.5%), about 2.0% (or 2.0%) or about 2.5% (or 2.5%) polymer-conjugated lipid (preferably PEGylated lipid). The lipids in the LNP may comprise (in mole %) at least 0.1, 0.5 or at least 0.8%, or preferably at least 1% polymer-conjugated lipid (preferably PEGylated lipid). The lipids in the LNP may comprise (in mole %) no more than 8.0, 6.0 or 4.0% or preferably no more than 3.0% polymer-conjugated lipid (preferably PEGylated lipid). Preferably, the neutral lipid is 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) or 1,2-dioleoyl-sn- glycero-3-phosphoethanolamine (DOPE), although other neutral lipids available to the skilled person may also be used. The lipids in the LNP may comprise (in mole %) 0-15.0, 0.1-15.0, 2.0-14.0, 5.0-13.0, 6.0-12.0 or 7.0- 11.0%, preferably 8.0-11.0% or 9.0-11.0% neutral lipid; such as about 9.4% (or 9.4%), about 9.6% (or 9.6%), about 9.8% (or 9.8%) or about 10.0% (or 10%) neutral lipid. The lipids in the LNP may comprise (in mole %) at least 0.1, 5.0 or at least 7.0%, or preferably at least 8.0% or at least 9.0% neutral lipid. The lipids in the LNP may comprise (in mole %) no more than 15.0, 13.0 or no more than 12.0%, or preferably no more than 11.0% neutral lipid. Exemplary sterols include cholesterol, cholesterol sulfate, desmosterol, stigmasterol, lanosterol, 7- dehydrocholesterol, dihydrolanosterol, symosterol, lathosteriol, 14-demethyl-lanosterol, 8(9)- dehydrocholesterol, 8(14)-dehydrocholesterol, 14-demethyl-14-dehydrolanosterol (FF-MAS), diosgenin, dehydroepiandrosterone sulfate (DHEA sulfate), dehydroepiandrosterone, sitosterol, lanosterol-95, 4,4-dimethyl(d6)-cholest-8(9), 14-dien-3β-ol (dihydro-FF-MAS-d6), 4,4-dimethyl(d6)- cholest-8(9)-en-3β-ol (dihydro T-MAS-d6), zymostenol, sitostanol, campestanol, camperstanol, 7- dehydrodesmosterol, pregnenolone, 4,4-dimethyl-cholest-8(9)-en-3β-ol (dihyrdro T-MAS), Δ5- avensterol, brassicasterol, dihydro FF-MAS, 24-methylene cholesterol, oxysterols, deuterated sterols, fluorinated sterols, sulfonated sterols, phosphorylated sterols, A-ring substituted sterols, cholest-5-ene- 3ß,4ß-diol, 5α-cholestan-3ß-ol, 4-cholesten-3-one, cholesta-8(9),24-dien-3-one, cholesta-8(9),24- Docket No: 70330WO01 dien-3-one, 2,2,3,4,4-pentadeuterio-5a-cholestan-3ß-ol, cholesteryl phosphocholine, cholesteryl-d7 pentadecanoate, cholesteryl-d7 palmitate, B-ring substituted sterols, cholestanol, 5ß,6ß-epoxy-d7, 3ß- hydroxy-5-cholestene-7-one, 6α-hydroxy-5α-cholestane, cholestanol, 5α,6α-epoxy, cholest-5-en- 3ß,7α-diol, cholest-5-en-3ß,7ß-diol, cholestanol, 5α,6α-epoxy-d7, Δ5,7-cholesterol, cholesta-5,8(9)- dien-3ß-ol, cholesta-5,8(14)-dien-3ß-ol, 7α-hydroxy-4-cholesten-3-one, zymostenol-d7, zymostenol, 7-dehydrodesmosterol, 3b,5a-dihydroxy-cholestan-6-one, D-ring substituted sterols, 3ß-hydroxy-5α- cholest-8(14)-en-15-one, 3ß-hydroxy-5α-cholestane-15-one, 5α-cholest-8(14)-ene-3ß,15α-diol, 5α- cholest-8(14)-ene-3ß,15ß,-diol, lanosterol-95, 5α-7,24-cholestadiene, 14-dehydro zymostenol, ergosta-5,7,9(11),22-tetraen-3ß-ol, cholest-5-ene-3ß,25-diol, cholest-(25R)-5-ene-3ß,27-diol, 24(R/S),25-epoxycholesterol, 24(S),25-epoxycholesterol, 24(R/S),25-epoxycholesterol-d6, cholest-5- ene-3ß,22(S)-diol, cholest-5-ene-3ß,22(R)-diol, cholest-5-ene-3ß,24(S)-diol, cholest-5-ene-3ß,24(R)- diol, 27-hydroxy-4-cholesten-3-one, campestanol, N,N-dimethyl-3ß-hydroxycholenamide, 25,27- dihydroxycholesterol, N,N-dimethyl-3ß-hydroxycholenamide, 25,27-dihydroxycholesterol, 5- cholestene-3β,20α-diol, 24S,25-epoxy-5α-cholest-8(9)-en-3β-ol, 24(S/R),25-epoxylanost-8(9)-en-3β- ol, 7-keto-27-hydroxycholesterol, 7α,27-dihydroxy-4-cholesten-3-one, 7α,27-dihydroxycholesterol, 7ß,27-dihydroxycholesterol, 5α,6ß-dihydroxycholestanol, 7α,25-dihydroxycholesterol, 7β,25- dihydroxycholesterol, 7α,24(S)-dihydroxycholesterol, 7α,24(S)-dihydroxy-4-cholesten-3-one, 7-keto- 25-hydroxycholesterol, 7α,24S,27-trihydroxycholesterol, dihydrotestosterone, testosterone, estrone, estrogen, estradiol, corticosterone, cortisol, or 24S,27-dihydroxycholesterol. Preferably, the sterol is cholesterol or a cholesterol-based lipid (e.g. any of those provided in the foregoing paragraph). The lipids in the LNP may comprise (in mole %) 20-80, 25-80, 30-70, 30-60, 35-60 or 40-60%, preferably 40-50% or 41-49% sterol; such as about 42% (or 42%), about 43% (or 43%), about 44% (or 44%), about 46% (or 46%), or about 48% (or 48%) sterol. The lipids in the LNP may comprise (in mole %) at least 20, 30 or at least 35%, or preferably at least 40% or at least 41% sterol. The lipids in the LNP may comprise (in mole %) no more than 80, 70 or no more than 60%, or preferably no more than 50% sterol. The lipids in the LNP may have the following mole % in combination: 30-60% cationic lipid (such as 35-55%, or preferably 40-50%), 35-70% sterol (such as 40-55%, or preferably 41-49%), 0.8-4.0% polymer-conjugated lipid (such as 0.8-3.5%, or preferably 1.0-3.0%), and 0-15% neutral lipid (such as 6.0-12.0% or preferably 8.0-11.0%). Docket No: 70330WO01 Such LNPs encapsulating RNA may be formed by admixing a first solution comprising the RNA with a second solution comprising lipids which form the LNP. The admixing may be performed by any suitable means available to the skilled person, e.g. a T-mixer, microfluidics, or an impinging jet mixer. Admixing may be followed by filtration to obtain a desirable LNP size distribution (e.g. those as detailed above in this subsection). The filtration may be performed by any suitable means available to the skilled person, e.g. tangential-flow filtration or cross-flow filtration. According, in a further independent aspect, the present disclosure provides a method of preparing an LNP encapsulating an RNA of the present disclosure, comprising admixing a first solution comprising the RNA and a second solution comprising lipids which form the LNP (e.g using the means as set out in the foregoing paragraph); and optionally filtering the obtained admixture (e.g using the means as set out in the foregoing paragraph). Pharmaceutical compositions In a further independent aspect, the present disclosure also provides a pharmaceutical composition comprising an RNA and/or carrier (preferably lipid nanoparticle) of the present disclosure. Such compositions typically further comprise a pharmaceutically acceptable excipient. Pharmaceutically acceptable excipients are well-known in the art, see, e.g. [22]. Such compositions are generally for immunising subjects against disease, preferably against RSV. Accordingly, pharmaceutical compositions of the present disclosure are generally considered vaccine compositions or immunogenic compositions. Pharmaceutical compositions of the present disclosure may comprise the RNA and/or carrier (preferably lipid nanoparticle) in plain water (e.g. water for injection “w.f.i.”) or in a buffer e.g. a phosphate buffer, a Tris buffer, a borate buffer, a succinate buffer, a histidine buffer, or a citrate buffer. Buffer salts will typically be included in the 5-20mM range. Pharmaceutical compositions of the present disclosure may have a pH between 5.0 and 9.5 e.g. between 6.0 and 8.0. Pharmaceutical compositions of the present disclosure compositions may include sodium salts (e.g. sodium chloride) to give tonicity. A concentration of 10±2 mg/mL NaCl is typical, e.g. about 9 mg/mL (or 9 mg/mL).. Pharmaceutical compositions of the present disclosure may include metal ion. These can prolong RNA stability by removing ions which can accelerate phosphodiester hydrolysis. Thus, such compositions may include one or more of EDTA, EGTA, BAPTA, pentetic acid, etc.. Such chelators are typically Docket No: 70330WO01 present at between 10-500 μΜ e.g. 0.1 mM. A citrate salt, such as sodium citrate, can also act as a chelator, while advantageously also providing buffering activity. Pharmaceutical compositions of the present disclosure may have an osmolality of between 200 mOsm/kg and 400 mOsm/kg, e.g. between 240-360 mOsm/kg, or between 290-310 mOsm/kg. Pharmaceutical compositions of the present disclosure may include one or more preservatives, such as thiomersal or 2-phenoxyethanol. Mercury-free compositions are preferred, and preservative-free vaccines can be prepared. Pharmaceutical compositions of the present disclosure may be aseptic or sterile. Pharmaceutical compositions of the present disclosure may be non-pyrogenic e.g. containing <1 EU (endotoxin unit, a standard measure) per dose, and preferably <0.1 EU per dose. Pharmaceutical compositions of the present disclosure may be gluten free. Pharmaceutical compositions of the present disclosure may be prepared in unit dose form. In some embodiments a unit dose may have a volume of between 0.1 -1.0 mL e.g. about 0.5mL (or 0.5mL). Pharmaceutical compositions of the present disclosure may be prepared as injectables, either as solutions or suspensions. The composition may be prepared for pulmonary administration e.g. by an inhaler, using a fine spray. The composition may be prepared for nasal, aural or ocular administration e.g. as spray or drops. Injectables for intramuscular administration are typical. Pharmaceutical compositions of the present disclosure comprise an immunologically effective amount of the RNA and/or carrier (preferably lipid nanoparticle), as well as any other components, as needed. Herein, “effective amount” and “immunologically effective amount” are used interchangeably. By “immunologically effective amount”, it is meant that the administration of that amount to an individual, either in a single dose or as part of a series, is effective for treatment or prevention, preferably prevention of RSV. This amount varies depending upon the health and physical condition of the individual to be treated, age, the taxonomic group of individual to be treated (e.g. non-human primate, primate, etc.), the capacity of the individual's immune system to synthesise antibodies, the degree of protection desired, the formulation of the vaccine, the treating doctor's assessment of the medical situation, and other relevant factors. It is expected that the amount will fall in a relatively broad range that can be determined through routine trials. The RNA content will generally be expressed in terms of the amount of RNA per dose. A preferred dose has <120µg RNA e.g. <100µg (e.g. 10-120µg or 10-100 µg, such as 10µg, 25µg, 50µg, 75µg or 100µg, or about 10µg, 25µg, 50µg, 75µg or 100µg), Docket No: 70330WO01 but expression can be seen at much lower levels e.g. <1µg/dose, <100ng/dose, <10ng/dose, <1ng/dose, etc. Pharmaceutical compositions of the present disclosure may further comprise an adjuvant (i.e. an agent that enhances an immune response in a non-specific manner). Pharmaceutical compositions of the present disclosure (preferably when comprising a lipid nanoparticle comprising an RNA of the present disclosure) may be lyophilised. In some embodiments, pharmaceutical compositions of the present disclosure comprise (i) an RNA encoding an RSV-F protein of the present disclosure, and (ii) a further RNA encoding at least one further protein. The RNA of (i) and (ii) may be comprised within the same carrier (preferably lipid nanoparticle), or within separate carriers (preferably lipid nanoparticles). In preferred embodiments, the at least one further protein is an antigen; and as such may comprise, or may be, a viral, bacterial, fungal, parasitic, tumour, or allergenic (i.e. from, or derived from, an allergen) antigen. The at least one further protein will typically be a pathogen antigen. The at least one further protein will typically be an antigen that is a surface polypeptide e.g. a spike glycoprotein, a haemagglutinin, an adhesin or an envelope glycoprotein. In a particular embodiment, the at least one further protein is an antigen from, or derived from, a virus, in particular a virus causing respiratory disease, in particular a seasonal virus causing respiratory disease. In embodiments wherein the at least one further protein is an antigen from, or derived from, a virus, examples of such viruses include: Coronavirus, Orthomyxovirus, Pneumoviridae, Paramyxoviridae, Poxviridae, Picornavirus, Bunyavirus, Heparnavirus, Filovirus, Togavirus, Flavivirus, Pestivirus, Hepadnavirus, Rhabdovirus, Caliciviridae, Retrovirus, Reovirus, Parvovirus, Herpesvirus, Papovaviruses and Adenovirus. In a preferred embodiment, the at least one further protein encoded by the RNA of (ii) is a further Pneumoviridae protein (in particular a Pneumoviridae antigen). Useful further Pneumoviridae proteins (in particular, antigens) can be from an Orthopneumovirus or Metapneumovirus, in particular human RSV or human Metapneumovirus (hMPV). Useful further hMPV antigens include e.g. the F, N, P, M, M2-1, and M2 antigens (in particular, the F antigen). Such hMPV proteins (in particular, antigens) may be from, or derived from, the A or B subtype. In a preferred embodiment, the RNA of (ii) encodes an hMPV antigen (in particular, the F antigen). In such embodiments, a preferred patient group (in which the pharmaceutical composition may be used in therapy, in particular vaccination) is infants (see section entitled Medical uses and methods of treatment, below). Useful further human RSV antigens encoded by the RNA of (ii) include e.g. the G, M1, M2-1, M2-2, P, L, N, NS1, NS2 and SH antigens, in addition to further RSV-F antigens, i.e. of distinct amino acid sequence to the RSV-F protein of the Docket No: 70330WO01 present disclosure. Such further human RSV proteins (in particular, antigens, in particular F antigens) may be from, or derived from, the A or B subtype, in particular the B subtype. In a preferred embodiment, the at least one further protein encoded by the RNA of (ii) is a Coronavirus antigen. Useful Coronavirus antigens can be from a SARS coronavirus, in particular SARS-CoV2. Useful Coronavirus antigens (preferably SARS-CoV2 antigens) include the spike, M, E, HE, Nuclocapsid, Plpro and 3CLPro proteins, in particular spike protein. Preferably, the Coronavirus antigen is a SARS-CoV2 spike protein. Said SARS-CoV2 spike protein may be from any variant, e.g. Omicron (such as Omicron BA.1, BA.2, BA3, BA.4 or BA.5), Alpha, Epsilon, Eta, Theta, Kappa, Iota, Zeta, Mu, Lambda, Beta, Gamma, or Delta. Preferably, said SARS-CoV2 spike protein includes one or more mutations relative to the wild-type protein, in particular one or more (e.g. two) mutations to proline resides. Said one or more mutations may be introduced to stabilise said SARS-CoV2 spike protein in its pre-fusion conformation. In a preferred embodiment, the RNA (ii) encodes a Coronavirus antigen, e.g. as detailed above. In such embodiments, a preferred patient group (in which the pharmaceutical composition may be used in therapy, in particular vaccination) is older adults (see section entitled Medical uses and methods of treatment, below). In another preferred embodiment, the at least one further protein encoded by the RNA of (ii) is an Orthomyxovirus antigen. Useful Orthomyxovirus antigens can be from an influenza A, B or C virus. Useful Orthomyxovirus antigens (in particular influenza A, B or C virus antigens) include the haemagglutinin, neuraminidase and matrix M2 proteins, in particular haemagglutinin. Preferably, the Orthomyxovirus antigen is an influenza A virus haemagglutinin. Said influenza A virus hemagglutinin may be from any subtype e.g. H1, H2, H3, H4, H5, H6, H7, H8, H9, H10, H11, H12, H13, H14, H15 or H16. In a preferred embodiment, the RNA of (ii) encodes an Orthomyxovirus antigen, e.g. as detailed above. In such RNA embodiments, a preferred patient group (in which the pharmaceutical composition may be used in therapy, in particular vaccination) is older adults (see section entitled Medical uses and methods of treatment, below). In such embodiments, the RNA of (ii) may encode an Orthomyxovirus antigen, e.g. as detailed above, and (iii) a third RNA may be present in the pharmaceutical composition which may encode a Coronavirus antigen, e.g. as detailed above in the preceding paragraph. In a further independent aspect, the present disclosure also provides a delivery device (e.g. syringe, nebuliser, sprayer, inhaler, dermal patch, etc.) comprising a pharmaceutical composition of the present disclosure. This device can be used to administer the composition to a vertebrate subject. In a further independent aspect, the present disclosure also provides a method of preparing a pharmaceutical composition, comprising formulating an RNA and/or carrier of the present disclosure Docket No: 70330WO01 with a pharmaceutically acceptable excipient, to produce said composition. In particular, said pharmaceutical composition has the features as detailed above throughout this section. In a further independent aspect, the present disclosure also provides a kit comprising an RNA and/or carrier, pharmaceutical composition or delivery device of the present disclosure, and instructions for use. Medical uses and methods of treatment The present disclosure also provides, in a further independent aspect, an RNA, carrier (preferably lipid nanoparticle) or pharmaceutical composition of the present disclosure, for use in medicine. Said use will generally be in a method for raising an immune response in a subject. The present disclosure also provides, in a further independent aspect, the use of an RNA, carrier (preferably lipid nanoparticle) or pharmaceutical composition of the present disclosure, in the manufacture of a medicament. Said medicament will generally be for raising an immune response in a subject. The present disclosure also provides, in a further independent aspect, a therapeutic method comprising the step of administering an effective amount of an RNA, carrier (preferably lipid nanoparticle) or pharmaceutical composition of the present disclosure to a subject (preferably a subject in need of such administration). Said method will generally be for raising an immune response in the subject. In another embodiment, the present disclosure provides a method of treatment of a subject comprising the step of administering an effective amount of the RNA of the present disclosure to the subject. In another embodiment, the present disclosure disclosed a method of treatment of a subject comprising administering to the subject an effective amount of the pharmaceutical composition of the present disclosure. In one embodiment, the pharmaceutical composition comprises an adjuvant. The immune response is preferably protective and, preferably involves antibodies and/or cell-mediated immunity. Generally, the subject is a vertebrate, preferably a mammal, more preferably a human or large veterinary mammal (e.g. horses, cattle, deer, goats, pigs), even more preferably a human. The RNA, carriers (preferably lipid nanoparticle) or pharmaceutical compositions of the present disclosure may be for use in the prevention, reduction or treatment of infection or disease. In addition, or alternatively, the RNA, carriers (preferably lipid nanoparticle) or pharmaceutical compositions of the present disclosure may be for use in the prevention, reduction or treatment of symptoms associated with infection or disease. The infection is generally one by, and said disease is generally one associated with, a Pneumoviridae virus. In preferred embodiments, the Pneumoviridae virus is an Docket No: 70330WO01 Orthopneumovirus, which is more preferably RSV, and even more preferable human RSV (including both the A and B subtypes thereof). Accordingly, the present disclosure also provides an RNA, carrier or pharmaceutical composition of the present disclosure; for use in treating or preventing RSV (preferably a method of vaccination against RSV). The present disclosure also provides the use of an RNA, carrier or pharmaceutical composition of the present disclosure, in the manufacture of a medicament for treating or preventing RSV (preferably wherein the medicament is a vaccine). The present disclosure also provides a method of inducing an immune response against RSV in a subject (preferably a method of vaccinating a subject against RSV), comprising administering to the subject an immunologically effective amount of the RNA, carrier or pharmaceutical composition of the present disclosure to the subject. Vaccination according to the present disclosure may either be prophylactic (i.e. to prevent infection) or therapeutic (i.e. to treat infection), but will typically be prophylactic. Such methods of vaccination may comprise administration of a single dose. Alternatively, such methods of vaccination may comprise a vaccination regimen (i.e. administration of multiple doses). Such regimens may involve the repeated administration of an immunologically identical protein antigen (delivered in at least one administration via an RNA of the present disclosure), in particular in a prime-boost regimen. In a prime-boost regimen, the first administration (“prime”) may induce proliferation and maturation of B and/or T cell precursors specific to one or more immunogenic epitopes present on the delivered antigen (induction phase). The second (and in some cases subsequent) administration (“boost”), may further stimulate and potentially select an anamnestic response of cells elicited by the prior administration(s). The different administrations may be given by the same or different routes e.g. a parenteral prime and mucosal boost, a mucosal prime and parenteral boost, etc. The prime administration(s) and boost administration(s) will be temporally separated, e.g. by at least: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or more months. In some embodiments, two prime administrations may be administered 3- 9 weeks apart (e.g.4-9, 5-9, 6-9, 7-9 or 7-8 weeks apart, or about two months apart), followed by one or more boost administrations 4-14 months after the second prime administration (e.g. 5-13, 6-13, 7- 13, 8-13, 9-13, 10-13 or 11-13 months, or about one year). In some embodiments, prime administration is to a naïve subject. In some embodiments, the antigen may be delivered in the prime and boost administrations as, or via, different formats. For example, the antigen may be delivered as a protein for the prime administration(s), and via an RNA of the present disclosure (in particular via a carrier comprising RNA) for the boost administration(s), or vice versa. Alternatively, different nucleic acid formats may be used, e.g. the protein antigen may be delivered via an RNA of the present disclosure (in particular via a carrier comprising RNA) for the prime administration(s), and a via a viral vector (e.g. an adenoviral vector) for the boost administration(s), or vice versa. Docket No: 70330WO01 The RNA, carriers, or pharmaceutical compositions of the present disclosure will generally be administered directly to the subject. Direct delivery may be accomplished by parenteral injection (e.g. subcutaneously, intraperitoneally, intravenously, intramuscularly, intradermally, or to the interstitial space of a tissue). Alternative delivery routes include rectal, oral (e.g. tablet, spray), buccal, sublingual, vaginal, topical, transdermal or transcutaneous, intranasal, ocular, aural, pulmonary or other mucosal administration. Preferably, the RNA, carriers, or pharmaceutical composition of the present disclosure will be administered intramuscularly or intradermally (in particular via a needle such as a hypodermic needle), more preferably intramuscularly. The RNA, carriers, or pharmaceutical compositions of the present disclosure may be used to elicit systemic and/or mucosal immunity. The subject of a method of vaccination according to the present disclosure may be a child (preferably an infant) or adult (preferably an older adult or pregnant female). Immunocompromised individuals may also be the subject of such vaccination (whether children or adults). Infant vaccination In a preferred embodiment, the RNA, carriers, or pharmaceutical compositions of the present disclosure are administered to infants (preferably human infants), as the subject of vaccination. The immune systems of infants are immature (see, e.g. [23]), hence this population is susceptible to RSV infection and resulting disease. Infant vaccination may prevent lower respiratory tract infection (in particular, bronchiolitis and (broncho-)pneumonia). The infant may be 0-12 months old. The infant may be less than one year old, such as less than: 11, 10, 9, 8, 7, 6, 5, 4 or less than 3 months old. The infant may be ≥one month old, such as ≥: 2, 3, 4, 5 or ≥6 months old. Preferably the infant is 2-6 months old (i.e. within and including the ages of 2 and 6 months), more preferably 2-4 months old. In a preferred embodiment, the infant was born from a female to whom an RSV vaccine (RNA, carrier, or pharmaceutical composition of the present disclosure) was administered, preferably while pregnant with said infant. The combination of maternal and infant vaccination may advantageously provide passive transfer of maternal antibodies (i.e. via the placenta and/or breast milk) to, in addition to active immunity generated by, the infant. Older adult vaccination In another preferred embodiment, RNA, carriers, or pharmaceutical compositions of the present disclosure are administered to older adults (preferably human older adults), as the subject of vaccination. Older adults may suffer from age-related immunosenescence (reviewed in, e.g. [24]), Docket No: 70330WO01 hence this population is also susceptible to RSV infection and resulting disease. Older adult vaccination may prevent lower respiratory tract infection (in particular, pneumonia). The older adult may be ≥50 years old, such as ≥: 55, 60, 65, 70, 75, 80, 85, 90, 95 or ≥100 years old. Preferably, the older adult is ≥60 or ≥65 years old (such as 60-120 or 65-120 years old). Pregnant female vaccination In another preferred embodiment, RNA, carriers, or pharmaceutical compositions of the present disclosure are administered to pregnant females (preferably pregnant human females), as the subject of vaccination. The primary object of maternal vaccination is to protect the infant from RSV infection when born, e.g. through passive transfer of antibodies via the placenta and/or breast milk. The pregnant female may be in her first, second or third trimester of pregnancy, preferably third trimester. The pregnant female may be ≥20 weeks pregnant, such as ≥: 22, 24, 26, 28, 30, 32, 34, 36 or ≥38 weeks pregnant. Preferably, the pregnant female is ≥28 , ≥29 or ≥30 weeks pregnant (such as 28-43, 29-43 or 30-43 weeks pregnant). General The practice of the present disclosure will employ, unless otherwise indicated, conventional methods of chemistry, biochemistry, molecular biology, immunology and pharmacology. The singular terms "a," "an," and "the" include plural referents unless context clearly indicates otherwise. Similarly, the word "or" is intended to include "and" unless the context clearly indicates otherwise. The term "plurality" refers to two or more. The term “at least one” refers to one or more. Unless specified otherwise, where a numerical range is provided, it is inclusive, i.e., the endpoints are included. The terms “at least”, “no more than” and other such terms preceding a list of values are applicable to all members of said list (not merely the first member thereof), unless otherwise stated. The term “comprising” encompasses “including” as well as “consisting” e.g. a composition “comprising” X may consist exclusively of X or may include something additional e.g. X + Y. The term “about” in relation to a numerical value x is optional and means, for example, x+10%. The word “substantially” does not exclude “completely” e.g. a composition which is “substantially free” from Y may be completely free from Y. Where necessary, the word “substantially” may be omitted from the definition of the present disclosure. Docket No: 70330WO01 References to charge, to cations, to anions, etc., are taken at pH 7. Embodiments The present disclosure also provides the following numbered embodiments. Combinations of features of the present disclosure presented below are exemplary, and not to be construed as exhaustive. 1. A recombinant RNA encoding an RSV-F protein comprising an F2 and an F1 domain; wherein the RSV-F protein further comprises, relative to a wild-type RSV-F sequence, the substitution of a residue for a C residue in both of the F2 and F1 domains. 2. The RNA of embodiment 1, wherein the wild-type RSV-F sequence is according to SEQ ID NO: 1 or 2. 3. A recombinant RNA encoding an RSV-F protein comprising an F2 and an F1 domain; wherein the RSV-F protein further comprises, relative to SEQ ID NO: 1 or 2, the substitution of a residue for a C residue in both of the F2 and F1 domains. 4. The RNA of any preceding embodiment, wherein the F2 domain is the region of the RSV-F protein corresponding to positions 26-109 of SEQ ID NO: 1 or 2, and wherein the F1 domain is the region of the RSV-F protein corresponding to positions 137-523 of SEQ ID NO: 1 or 2. 5. The RNA of any preceding embodiment, wherein, when expressed, the RSV-F protein comprises a disulphide bond formed by the C residues in the F2 and F1 domains. 6. The RNA of any preceding embodiment, wherein the C residue in the F1 domain is within the fusion peptide, optionally wherein the fusion peptide is the region corresponding to positions 137- 157 of SEQ ID NO: 1 or 2. 7. The RNA of embodiment 6, wherein the C residue in the F1 domain is within the region of the RSV-F protein corresponding to positions 143-153, 146-150 or 147-149 of SEQ ID NO: 1 or 2. 8. The RNA of embodiment 7, wherein the C residue in the F1 domain is at position 148 of the RSV- F protein. 9. The RNA of any preceding embodiment, wherein the C residue in the F2 domain is within the region of the RSV-F protein corresponding to positions 99-105, 100-104 or 102-104 of SEQ ID NO: 1. 10. The RNA of embodiment 9, wherein the C residue in the F2 domain is at position 103 of the RSV- F protein. Docket No: 70330WO01 11. The RNA of any preceding embodiment, wherein the RSV-F protein comprises, relative to a wild- type RSV-F sequence such as according to SEQ ID NO: 1 or 2, the substitutions T103C and I148C. 12. The RNA of any preceding embodiment, wherein the RSV-F protein comprises, relative to a wild- type RSV-F sequence such as according to SEQ ID NO: 1 or 2, the substitution of a D or E residue for S, T, N, H, P, F, L or Q within the region of the RSV-F protein corresponding to positions 474- 523 of SEQ ID NO: 1 or 2. 13. The RNA of embodiment 12, wherein the RSV-F protein comprises the substitution D486S/H/N/T/P or the substitution E487Q/T/S/L/H; optionally D486S/T/N/P. 14. The RNA of embodiment 13, wherein the RSV-F protein comprises the substitution D486S. 15. The RNA of any preceding embodiment, wherein the RSV-F protein further comprises, relative to a wild-type RSV-F sequence such as according to SEQ ID NO: 1 or 2, the substitution of a S, T, G, A, V, or R residue that is buried in the pre-fusion conformation for a I, Y, L, H, M or W residue. 16. The RNA of any preceding embodiment, wherein the RSV-F protein further comprises, relative to a wild-type RSV-F sequence such as according to SEQ ID NO: 1 or 2, the substitution of an S residue at position 190, 55, 62, 155, or 290 of the RSV-F protein for I, Y, L, H, or M; optionally said substitutions at position 190. 17. The RNA of embodiment 16, wherein the RSV-F protein comprises the substitution S190I. 18. The RNA of any preceding embodiment, wherein the RSV-F protein comprises, relative to a wild- type RSV-F sequence such as according to SEQ ID NO: 1 or 2, the substitutions T103C, I148C, S190I and D486S. 19. A recombinant RNA encoding an RSV-F protein, wherein the RSV-F protein comprises: a C residue at position 103, a C residue at position 148, an I residue at position 190, and an S residue at position 486. 20. The RNA of embodiment 19, wherein, when expressed, the RSV-F protein comprises a disulphide bond formed by the C residues. Docket No: 70330WO01 21. The RNA of any preceding embodiment, wherein, when expressed, the RSV-F protein is in the pre-fusion conformation. 22. The RNA of any preceding embodiment, wherein the RSV-F protein comprises an amino acid sequence having at least 70%, 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.3% sequence identity to SEQ ID NO: 1. 23. The RNA of any preceding embodiment, wherein the RSV-F protein comprises an F2 domain comprising or consisting of an amino acid sequence having at least 70%, 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to positions 1-109 of SEQ ID NO: 1; and an F1 domain comprising or consisting of an amino acid sequence having at least 70%, 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5%, sequence identity to positions 137-523 of SEQ ID NO: 1. 24. The RNA of any preceding embodiment, wherein the RSV-F protein comprises an F2 domain comprising or consisting of an amino acid sequence having at least 70%, 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to positions 26-109 of SEQ ID NO: 1; and an F1 domain comprising or consisting of an amino acid sequence having at least 70%, 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5%, sequence identity to positions 137-523 of SEQ ID NO: 1. 25. The RNA of any preceding embodiment, wherein the RSV-F protein is of the A subtype. 26. The RNA of any of embodiments 1-21, wherein the RSV-F protein comprises an amino acid sequence having at least 70%, 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to SEQ ID NO: 2. 27. The RNA of any of embodiments 1-21 or 26, wherein the RSV-F protein comprises an F2 domain comprising or consisting of an amino acid sequence having at least 70%, 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to positions 1-109 of SEQ ID NO: 2; and an F1 domain comprising or consisting of an amino acid sequence having at least 70%, 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5%, sequence identity to positions 137-523 of SEQ ID NO: 2. Docket No: 70330WO01 28. The RNA of any of embodiments 1-21, 26 or 27, wherein the RSV-F protein comprises an F2 domain comprising or consisting of an amino acid sequence having at least 70%, 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to positions 26-109 of SEQ ID NO: 2; and an F1 domain comprising or consisting of an amino acid sequence having at least 70%, 75%, 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5%, sequence identity to positions 137-523 of SEQ ID NO: 2. 29. The RNA of any of embodiments 1-21, 26, 27 or 28, wherein the RSV-F protein is of the B subtype. 30. The RNA of any preceding embodiment, wherein the RSV-F protein comprises an E residue at position 66, and a P residue at position 101. 31. The RNA of any preceding embodiment, wherein the RNA is for immunisation of a subject. 32. The RNA of any preceding embodiment, which is non-self-replicating RNA. 33. The RNA of any of embodiments 1-31, which is self-replicating RNA. 34. The RNA of any of preceding embodiment, comprising, in the 5’ to 3’ direction: a 5’ Cap, a 5’ UTR, an open reading frame encoding the RSV-F protein, a 3’UTR, and a 3’ poly-A tail. 35. The RNA of embodiment 34, wherein the 5’ cap comprises a 7-methylguanosine linked 5’-to-5’ to the 5’ first ribonucleoside by a triphosphate bridge, and wherein the first 5’ ribonucleoside comprises a 2’-methylated ribose (2’-O-Me). 36. The RNA of embodiment 34, wherein the 5’ cap comprises a 7-methyl-3'-O-methylguanosine linked 5’-to-5’ to the 5’ first ribonucleoside by a triphosphate bridge, and wherein the first 5’ ribonucleoside comprises a 2’-methylated ribose (2’-O-Me). 37. The RNA of any of embodiments 34-36, wherein the 3’ poly-A tail comprises a contiguous stretch of 100-500 A ribonucleotides. 38. The RNA of any of embodiments 34-36, wherein the 3’ poly-A tail comprises at least two non- contiguous stretches of A ribonucleotides; optionally 25-35 and 65-90 ribonucleotides in length respectively; optionally orientated in the 5’ to 3’ direction. 39. The RNA of any preceding embodiment, comprising a modified ribonucleotide. 40. The RNA of embodiment 39, wherein the modified ribonucleotide is 1mΨ Docket No: 70330WO01 41. The RNA of embodiment 40 wherein the RNA comprises 1mΨ and neither standard U ribonucleotides nor other modified U ribonucleotides; optionally wherein the RNA comprises 1mΨ and neither standard U ribonucleotides nor other modified ribonucleotides. 42. The RNA of any preceding embodiment, wherein the RNA has a GC content of 30-70%, 40-60%, 45-55%, 46-53%, 47-51%, or 48-50%. 43. The RNA of any of embodiments 1-41, wherein the RNA has a GC content of 30-70%, 40-70%, 45-70%, 50-70%, or 55-70%. 44. The RNA of any preceding embodiment, wherein the 5’ UTR comprises (i) an RNA sequence according to SEQ ID NO: 18 or (ii) an RNA sequence at least 70%, 80%, 85%, 90%, 95% or at least 97% identical to SEQ ID NO: 18. 45. The RNA of any preceding embodiment, wherein the 3’ UTR comprises (i) an RNA sequence according to SEQ ID NO: 19 or (ii) an RNA sequence at least 70%, 80%, 85%, 90%, 95%, 97% or at least 98% identical to SEQ ID NO: 19. 46. The RNA of any of any preceding embodiment, wherein the RNA comprises of consists of (i) SEQ ID NO: 4; or (ii) an RNA sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or at least 99.9% identical to SEQ ID NO: 4. 47. The RNA of any of embodiments 1-42 or 46, wherein the 5’ UTR comprises (i) an RNA sequence according to SEQ ID NO: 20 or (ii) an RNA sequence at least 70%, 80%, 85%, 90%, 95%, 97% or at least 98% identical to SEQ ID NO: 20. 48. The RNA of any of embodiments 1-42, 46 or 47, wherein the 3’ UTR comprises (i) an RNA sequence according to SEQ ID NO: 21 or (ii) an RNA sequence at least 70%, 75%, 80%, 85%, 90% 95%, 96%, 97%, 98%, 99% or at least 99.5% identical to SEQ ID NO: 21. 49. The RNA of any preceding embodiment, wherein the RNA comprises an open reading frame comprising or consisting of: (i) positions 32-1753 of SEQ ID NO: 4; or (ii) an RNA sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or at least 99.9% identical to positions 32-1753 of SEQ ID NO: 4. 50. The RNA of any preceding embodiment, wherein the RNA is able to elicit a pre-fusion RSV-F- specific antibody response in vivo. 51. The RNA of embodiment 50, wherein the antibody response is an IgG response. Docket No: 70330WO01 52. The RNA of any preceding embodiment, wherein the RNA is able to elicit a neutralising antibody response against RSV in vivo. 53. The RNA of embodiment 52, wherein the RSV is of the A subtype. 54. The RNA of any preceding embodiment, wherein the RNA is able to elicit a cross-neutralising antibody response against strains of both RSV-A and RSV-B subtypes in vivo. 55. An RNA vaccine comprising the RNA of any preceding embodiment. 56. A carrier comprising the RNA or RNA vaccine of any of embodiments 1-55. 57. The carrier of embodiment 56, which is a lipid nanoparticle. 58. The lipid nanoparticle of embodiment 57, comprising a mixture of cationic lipids, neutral lipids, sterols and polymer-conjugated lipids. 59. The lipid nanoparticle of embodiment 58, wherein the cationic lipid has a pKa of 5.0-8.0; optionally 5.0-7.6. 60. The lipid nanoparticle of embodiment 58 or 59, wherein the cationic lipid comprises a tertiary amine group. 61. The lipid nanoparticle of any of embodiments 57-60, wherein the polymer-conjugated lipid is a PEGylated lipid; optionally wherein the PEG has a weight average molecular weight of 1-3 kDa. 62. The lipid nanoparticle of any of embodiments 58-61, wherein the sterol is cholesterol or a cholesterol-based lipid. 63. The lipid nanoparticle of any of embodiments 58-62 comprising (in mole %) 30-60% cationic lipid, 35-70% sterol, 0.8-4.0% polymer-conjugated lipid, and 0-15% neutral lipid; optionally 40-50% cationic lipid, 41-49% sterol, 1.0-3.0% polymer-conjugated lipid and 8.0-11.0% neutral lipid. 64. The lipid nanoparticle of any of embodiments 58-63, wherein the molar ratio of protonatable nitrogen atoms in the cationic lipid to phosphates in the RNA (“N:P ratio”) is 5.0-8.0, 5.5-7.0, 5.5- 6.5, 5.0-6.0 or 5.5-6.0. 65. A pharmaceutical composition comprising the RNA or RNA vaccine of any of embodiments 1-55, or carrier of any of embodiments 56-64; optionally comprising a pharmaceutically acceptable excipient; optionally further comprising an adjuvant. Docket No: 70330WO01 66. A vaccine composition comprising the RNA or RNA vaccine of any of embodiments 1-55, or carrier of any of embodiments 56-64; optionally comprising a pharmaceutically acceptable excipient; optionally further comprising an adjuvant 67. The composition of embodiment 65 or 66, for use in medicine. 68. The composition for use of embodiment 67, for use in a method of raising an immune response in a subject; optionally a protective immune response in a subject. 69. The composition for use of embodiment 67 or 68, for use in the treatment or prevention of RSV. 70. The composition for use of embodiment 69, for use in a method of vaccinating a subject against RSV; optionally wherein the vaccination is prophylactic. 71. The composition for use of any of embodiments 68-70, wherein the subject is a human infant; optionally 2-6 months old. 72. The composition for use of any of embodiments 68-70, wherein the subject is a human older adult; optionally ≥50 years old, optionally ≥60 years old. 73. The composition for use of any of embodiments 68-70, wherein the subject is a pregnant human female; optionally ≥28 weeks pregnant. 74. A method of inducing an immune response against RSV in a subject, comprising administering to the subject an immunologically effective amount of the RNA or RNA vaccine of any of embodiments 1-55, carrier of any of embodiments 56-64, pharmaceutical composition of embodiment 65, or vaccine composition of embodiment 66. 75. Use of the RNA or RNA vaccine of any of embodiments 1-55, or carrier of any of embodiments 56-64, in the manufacture of a medicament. 76. Use according to embodiment 75, wherein the medicament is for treating or preventing RSV. 77. Use according to embodiment 76, wherein the medicament is a vaccine; optionally a prophylactic vaccine. 78. A kit comprising the RNA or RNA vaccine of any of embodiments 1-55, carrier of any of embodiments 56-64, pharmaceutical composition of embodiment 65, or vaccine composition of embodiment 66, and instructions for use. Docket No: 70330WO01 EXAMPLES Many modifications and variations of the present disclosure are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, a skilled person in the art would recognise that the invention may be practiced otherwise than as specifically described. The illustrative embodiments and examples should not be construed as limiting the invention. Materials & Methods Cloning and expression of RSV-F monoclonal antibodies (Example 1) Plasmids encoding RSV-F antibodies, AM14, D25 and Motavizumab were transiently transfected in Expi293F cells (THERMO FISHER SCIENTIFIC) according to manufacturer’s instructions and media was harvested 6-7 days post transfection. The cell harvest media was passed over a MABSELECT SURE COLUMN (CYTIVA) and eluted with 0.1 M citrate pH 3 into 1 M Tris pH 9; buffer exchanged into 20 mM HEPES pH 7, 150 mM NaCl; followed by a final size exclusion chromatography step on a HILOAD 16/600 Superdex 30 pg column (CYTIVA) in 20 mM Hepes pH 7, 150 mM NaCl. Cloning of specific RSV-F mutants from mRNA (Example 1) RSV F wildtype (strain A2) protein sequence (SEQ ID NO: 1) was back-translated to a nucleic acid sequence using specific metrics for codon optimality. The DNA gBLOCKS (INTEGRATED DNA TECHNOLOGIES) were amplified by PCR, and ligation into a vector with a polyA tail. Amino acid substitutions N67I and S215P (also known as design F(ii) were incorporated in DNA constructs and encoded in the eventual mRNA and protein. The additional variations (also known as DS-Cav1, F(iii), and F(i) and their amino acid substitutions are shown in the Table 1. The PCR reaction was heated to 98 °C for 30 seconds, followed by 16 cycles at 98 °C for 10 seconds, 69 °C for 30 seconds, 72 °C for 30 seconds. and a final extension of 72 °C for 2 min. The PCR products were treated with KLD enzyme (NEB E0554) at room temperature for 5 minutes. Transformation with competent cells (NEB C3040H) was carried out by following manufacture instructions. 24 hours after, colonies were picked and screened to identify correct sequences. In the DNA sequences, the T7 promotor region and the UTRs were appended to 5’ and 3’ of the coding regions (5’ and 3’ “UTR4”) and a polyA tail is after 3’ UTR region. The final plasmids were validated by Sanger sequencing and purified for mRNA production. Table 1 – substitutions in mRNAs designs tested in cell-based assay Design Substitutions relative to wild-type mRNA construct designation protein sequence (SEQ ID NO: 1) DS-Cav1 (control) S115C, S190F, V207L, S290C XW02 (SEQ ID NO: 25) Docket No: 70330WO01 F(ii) (control) N67I, S215P KM135 (SEQ ID NO: 22) F(i) T103C, I148C, S190I, D486S KM173 (SEQ ID NO: 4) F(iii) (control) ^104-144; A149C, S155C, S190F, KM126 (SEQ ID NO: 24) V207L, S290C, L373RC, Y458C; ^ ^ ^ ^-574* *Different wild-type sequence to SEQ ID NO: 1 (against which mutations have been made) In vitro transcription to generate mRNA for RSV-F variations (Example 1) The plasmids were linearized with the BspQI restriction enzyme (NEW ENGLAND BIOLABS) to produce the DNA templates for in vitro transcription. mRNAs were produced by in vitro transcription with capping analogue (TRILINK CLEANCAP A/G) and 100% uridine replacement (with 1mΨ), followed with DNase I, phosphatase treatments (NEW ENGLAND BIOLABS) and silica column purification (QIAGEN). Newly synthesized mRNAs were validated by Tapestation (Agilent) and denaturing RNA gels. Cell culture conditions (Example 1) Primary BJ cells (ATCC, CRL-2522) were maintained by routine passaging in growth media (DMEM (LONZA 12-614F) supplemented with 10% FBS (CORNING 35-016-CV), antibiotic (GIBCO 15140- 122) and glutamine (GIBCO 25030-081) and grown at 37°C, 5% CO₂. Forward transfection of candidate mRNAs (Example 1) BJ cells were seeded in growth media at 1.5x105 cells/mL onto 96-well, clear-bottom, black-walled imaging microwell plates (PERKIN ELMER 6055302). The following day, target mRNAs were complexed with TRANSIT mRNA transfection reagent (MIRUS mir2250) in OPTIMEM (GIBCO 31985-070). Each target mRNA was forward transfected into BJ cell monolayers using 0.35% transfection reagent (final concentration) with mRNAs diluted to 0.454ng/uL (final concentration), or water-only negative control. The transfected BJ cells were incubated according to the time-course assay. Indirect immunofluorescent labelling and detection of surface-expressed RSV F (Example 1) At the appropriate hours post-transfection (hpt), (24 and 72), the cell media was removed from cells in 96-well format and cell monolayers were rinsed once with PBS with calcium and magnesium (THERMOFISHER 14080055). The cell monolayers were fixed in 4% paraformaldehyde (THERMOFISHERSCIENTIFIC J19943-K2) for 15min. Fixed cells were stored in PBS at 4C until cells can be immunolabeled as a batch. Docket No: 70330WO01 The fixed cell monolayers were rinsed twice with PBS (VWR 02-0119-1000). Nonspecific antibody- binding for fixed cells was blocked using 1% Normal Horse Serum (GIBCO 16050-130) in PBS (1%NHS-PBS). RSV F protein was labelled by incubating cell monolayers with the respective human anti-RSV F monoclonal antibodies: AM14, D25, motavizumab. Each well was incubated with 331ng of the respective antibody in blocking media overnight at 4C. Cell monolayers are rinsed 3 times with 1%NHS-PBS. Indirect immunofluorescent detection of RSV F expression was completed by incubating cell monolayers with goat anti-human antibody with ALEXA647 (THERMOFISHER A- 21445) diluted 1:2000 in 1%NHS-PBS. Additionally, cell nuclei were co-labelled with DYECYCLE Violet (THERMOFISHER V35003) following manufacturer’s recommendations. Cell monolayers are rinsed 3 times with 1% NHS-PBS then cells are stored in PBS for imaging. 9 fields per well were imaged in the DYECYCLE Violet and Alexa647 fluorescent channels using the 10x objective on the THERMOSCIENTIFIC Cell Insight CX7 automated imaging system. Image analysis is completed using the Target Activation protocol associated with the CELLOMICS (HCS NAVIGATOR Ver 6.6.2 Build 8533) image analysis system. Data analysis was completed using MICROSOFT EXCEL and PRISM GRAPHPAD. In vivo RNA immunisation (Example 2) All recombinant RNA molecules were produced by in vitro transcription using N1-methyl pseudouridine to replace all uridines. All recombinant RNA molecules comprised a cap-1 5’ cap (TRILINK CLEANCAP) and a 3’ poly(A) tail. The mRNAs were purified and evaluated for mRNA integrity (by capillary and glyoxal denaturing gel electrophoresis). The RV39 LNP mRNA constructs were then formulated in LNPs comprising 40 mol% cationic lipid RV39; 2 mol% PEG-conjugated lipid; 48 mol% cholesterol; and 10 mol% 1,2-diastearoyl-sn-glycero- 3-phosphocholine (DSPC). Female BALB/c mice were 7 - 8 weeks old at day 0 of the study. An insulin syringe with a permanently attached needle was used to administer 50 µL (25 µL in each hindleg thigh muscle) of either saline or a high (2 µg) or low (0.2 µg) dose of F(iii) F(i), F(ii) or DS-Cav1 (high dose only) into each mouse on day 0 and day 21 (mRNA constructs KM126, KM173, KM135 and XW02 – SEQ ID NOs: 24, 4, 22 and 25 respectively). The groups of animals, formulation lot numbers, stock concentrations, number of vials, and storage temperatures were as follows (Table 2): Table 2 –in vivo RNA immunisation study design Stock Dose Number Number Storage Immunoge Lot Concentratio of vials of Temperature n Number n supplied Animals (°C) Docket No: 70330WO01 As Supplied Saline NA from NA NA 5 RT Manufacturer 2µg 8 F(iii) 59 µg/mL LNPs 32886a 2 vials for (RV39) 0.2µg 2 ug dose 8 (1.1 mL material 2µg per vial) 8 F(i) LNPs 52 µg/mL (RV39) 32886b 0.2µg 2 vials for ⁸ -80°C 0.2 ug dose (0.3 2µg mL ⁸ F(ii) LNPs 48 µg/mL materia RV39) 328 l ( 86d per vial) 0.2µg ⁸ 65 µg/mL DS-Cav1 LNPs 32886f 2µg 8 (RV39) On day 21, mice were anesthetized under isoflurane to collect 100 μL of whole blood (40 μL of serum) by submandibular collection method. On day 35, mice were anesthetized under isoflurane and terminally exsanguinated by cardiac stick to obtain an estimated 200 μL to 500 μL of whole blood, (100 μL of serum). RSV pre-F IgG binding antibody titres and RSV A neutralizing antibody titres were measured on day 21 and day 35 using the following assays. IgG Binding Assay: The LUMINEX assay was designed to measure the levels of RSV Pre-Fusion protein specific IgG binding antibodies from immunized mice. LUMINEX microspheres (MAGPLEX microspheres, LUMINEX CORP from Austin, TX) were coupled with RSV preF antigen using sulfo- NHS and EDC, according to manufacturer’s instructions. In a 96-well plate, 2,000 microspheres/well Docket No: 70330WO01 are added in a volume of 50 µl PBS with 1% BSA + 0.05% Na Azide (assay buffer) to 100 µl of mouse serum serial diluted. After incubation of the microspheres and serum on an orbital shaker, covered, at RT for 60 minutes, the microspheres are washed 2 times with 200 µl/well of PBS, 0.05% Tween-20 (wash buffer) on a plate washer using a magnet to allow settling of beads between washes. Following the wash, 50 µL/well of r-Phycoerythrin (r-PE) conjugated anti-mouse IgG (JACKSON IMMUNORESEARCH) was added, and plates are incubated, covered, on an orbital shaker at RT for 60 minutes. After a final plate wash (same as described above), the samples were resuspended in PBS, covered, and incubated at RT on an orbital shaker for 20 minutes. Fluorescent intensity is measured using a LUMINEX FLEXMAP 3D. The raw data was analyzed using a SOFTMAX PRO template, where the serum sample binding potency was interpolated based on a four-parameter logistic fit of the standard curve. Serum anti-RSV preF IgG binding was calculated in terms of Assay Units (AU) using a reference standard assigned to a concentration of 100 AU. RSV A neutralizing antibody titre assay: Heat-inactivated sera (incubated for 30 min at 56°C) were diluted 3-fold starting at 1/8 (for a final dilution of 1/16). A control serum (WYETH Human Reference Sera from WHO/NIBSC) was included at a starting dilution of 1/64 (1/128 final). For the serial dilutions, 30μL of diluted serum was added on top of 60μL of RSV media (Biorich DMEM supplemented with 3%-fetal bovine serum (FBS; MOREGATE, FBSAE1000), 2 mM L-Glutamine, and 50 μg/mL Gentamicin). RSV lab-adapted A-Long virus was diluted to approximately 50-150 foci- forming units per 25μL. 60μL of virus was added into the wells with the same volume of serum dilutions and incubated for 2 hours at 35°C 5% CO2. After incubation, 50μL of the serum-virus mixture was added on top of the vero cells (seeded the day before the test at a density of 15000 cells/well, to reach a minimum of 80% confluency) and incubated for 2 hours at 35°C 5% CO2. After incubation, serum-virus supernatant was removed and 200μL of 0.5% carboxymethyl cellulose + RSV media was added on top of the cells. Plates were incubated for 2 days (max of 42 hours) at 35°C 5% CO₂. Plates were then washed 2 times with 100μL of PBS and 50μL of 1% paraformaldehyde was added per well. Plates were covered in aluminium and incubated overnight at 4°C. The next day, plates were rinsed 3 times with 150μL of PBS.100μL of blocking solution (2% milk + PBS) was added on top of the wells and incubated for 1 hour at 37°C. After incubation, plates were rinsed 3 times with 200μL of PBS. 50μL of primary goat anti-RSV polyclonal Ab (BIODESIGN, B65860G) diluted 1:400 in blocking solution was added per well and plates were incubated for 1 hour at 37°C.50μL of secondary Ab rabbit anti-goat HRP (AGRISERA, AS10659) diluted 1:1500 in blocking solution was added per well and plates were incubated for 1 hour at 37°C. After 1 hour, plates were rinsed 3 times with 200μL of PBS and 50μL of TRUEBLUE Peroxidase substrate (KPL, 5510-0049) was added on top. After an incubation for 5-15 minutes, plaques were then washed extensively with DI water and let to dry. Docket No: 70330WO01 Imaging of the plaques was done using an AXIOVISION microscope. Effective dilution 60 (ED60) values, corresponding to the reciprocal serum dilution associated with 60% reduction in FFU counts, were determined using a linear model. In vivo RNA immunisation (Example 4) All recombinant RNA molecules were produced by in vitro transcription using N1-methyl pseudouridine to replace all uridines. All recombinant RNA molecules comprised a cap-1 5’ cap (TRILINK CLEANCAP) and a 3’ poly(A) tail. The mRNAs were purified and evaluated for mRNA integrity (by capillary and glyoxal denaturing gel electrophoresis). The RV39 LNP mRNA constructs were then formulated in LNPs comprising 40 mol% cationic lipid RV39; 2 mol% PEG-conjugated lipid; 48 mol% cholesterol; and 10 mol% 1,2-diastearoyl-sn-glycero- 3-phosphocholine (DSPC). Female BALB/c mice were 7 - 8 weeks old at day 0 of the study. An insulin syringe with a permanently attached needle was used to administer 50 µL (25 µL in each hindleg thigh muscle) of either saline or 0.5 µg dose of F(i), F(ii), F(iii) or DS-Cav1 into each mouse on day 0 and day 21. The groups of animals, formulation lot numbers, stock concentrations, number of vials, and storage temperatures were as follows: Table 3 – in vivo RNA immunisation study design Lot Stock Dos Number Number Storage Immunogen e of vials of Temperature Number Concentration supplied Animals (°C) As Supplied Saline NA from NA NA 3 RT Manufacturer F(iii) LNPs (RV39) 39371f 57 µg/mL 17 2 vials F(i) 39371g 56 µg 0.5µ (1.2 mL LNPs (RV39) /mL g material 17 -80 per vial) F(ii) LNPs (RV39) 39371h 53 µg/mL 17 Docket No: 70330WO01 DS-Cav1 LNPs (RV39) 39371i 57 µg/mL 17 Table 4 –in vivo RNA immunisation study – construct details RSV-F construct mRNA construct designation F(iii) KM126 F(i) KM173 F(ii) KM135 DS-Cav1 XW02 On day 21, mice were anesthetized under isoflurane to collect 100 μL of whole blood (40 μL of serum) by submandibular collection method. On day 35, mice were anesthetized under isoflurane and terminally exsanguinated by cardiac stick to obtain an estimated 200 μL to 500 μL of whole blood, (minimum 100 μL of serum). RSV pre-F and post-F IgG binding antibody titres and RSV neutralising antibody titres were measured on day 21 and day 35 using the following methods. RSV A neutralising antibody titre assay (against RSV A and B strains): Heat-inactivated sera (incubated for 30 min at 56°C) were diluted 3-fold starting at 1/8 (for a final dilution of 1/16). A control serum (WYETH Human Reference Sera from WHO/NIBSC) was included at a starting dilution of 1/64 (1/128 final). For the serial dilutions, 30μL of diluted serum was added on top of 60μL of RSV media (BIORICH DMEM supplemented with 3%-fetal bovine serum (FBS; MOREGATE, FBSAE1000), 2 mM L-Glutamine, and 50 μg/mL Gentamicin). RSV A and B strain viruses were diluted to approximately 50-150 foci-forming units per 25μL.60μL of virus was added into the wells with the same volume of serum dilutions and incubated for 2 hours at 35°C 5% CO2. After incubation, 50μL of the serum-virus mixture was added on top of the vero cells (seeded the day before the test at a density of 15000 cells/well, to reach a minimum of 80% confluency) and incubated for 2 hours at 35°C 5% CO2. After incubation, serum-virus supernatant was removed and 200μL of 0.5% carboxymethyl cellulose + RSV media was added on top of the cells. Plates were incubated for 2 days (max of 42 hours) at 35°C 5% CO₂. Plates were then washed 2 times with 100μL of PBS and 50μL of 1% paraformaldehyde was added per well. Plates were covered in aluminium and incubated overnight Docket No: 70330WO01 at 4°C. The next day, plates were rinsed 3 times with 150μL of PBS.100μL of blocking solution (2% milk + PBS) was added on top of the wells and incubated for 1 hour at 37°C. After incubation, plates were rinsed 3 times with 200μL of PBS.50μL of primary goat anti-RSV polyclonal Ab (BIODESIGN, B65860G) diluted 1:400 in blocking solution was added per well and plates were incubated for 1 hour at 37°C. 50μL of secondary Ab rabbit anti-goat HRP (AGRISERA, AS10659) diluted 1:1500 in blocking solution was added per well and plates were incubated for 1 hour at 37°C. After 1 hour, plates were rinsed 3 times with 200μL of PBS and 50μL of TRUEBLUE Peroxidase substrate (KPL, 5510- 0049) was added on top. After an incubation for 5-15 minutes, plaques were then washed extensively with DI water and let to dry. Imaging of the plaques was done using an AXIOVISION microscope. Effective dilution 60 (ED60) values, corresponding to the reciprocal serum dilution associated with 60% reduction in FFU counts, were determined using a linear model. RSV F IgG Binding: A multiplex assay was performed to evaluate titers of RSV pre-F- and post-F- specific antibodies in the serum of the mice immunized with new non replicating RSV mRNA vaccines. LUMINEX microspheres (MAGPLEX microspheres, LUMINEX from Austin, TX) were coupled with RSV post-F and pre-F antigen by chemical coupling according to manufacturer instructions. In 96 well plates, 2000 microspheres/ well were added in a volume of 50 µL 1X PBS with 1% BSA + 0.05% Na Azide (assay buffer) to five-fold serial dilutions of mouse serum down each column. After incubation of the microspheres and serum on an orbital shaker, covered, at RT for 60 minutes, the microspheres were washed two times with 200 µL/well of PBS with 0.05% Tween-20 (wash buffer) on a plate washer using a magnet to allow settling of beads between washes. Following the wash, 50 µL/well of r-Phycoerythrin (r-PE) conjugated anti-mouse IgG (JACKSON IMMUNORESEARCH) was added at a 1:50 dilution, and plates were incubated (covered) on an orbital shaker at room temperature (RT) for 60 minutes. After a final plate wash (same as described above) and incubation (covered, RT) with PBS on an orbital shaker for 20 minutes, fluorescent intensity was measured using a LUMINEX FLEXMAP 3D (LIFE TECHNOLOGIES model FM3D000). The raw data was analyzed using a SOFTMAX PRO template, where the serum sample binding potency was interpolated based on a five-parameter logistic fit of the standard curve. Serum anti-RSV F binding was calculated in terms of ASSAY Units (AU) using a reference standard assigned to a concentration of 100 AU. Example 1 The RSV F protein variants F(i), F(ii), F(iii) and DS-Cav1, having the substitutions relative to wild- type set out in in Table 1, were all encoded into mRNA and expressed in BJ cells as set out in the Materials and Methods. While the level of RSV-F expression measured varied across a broad range (Figures 1A, C, E, G, I & K), transfection of diverse mRNAs and the expressed cognate proteins did Docket No: 70330WO01 not meaningfully impact the integrity of the cell monolayers at either 24 (Figure 1B, F & J) or 67 hours post transfection (Figure 1D, H & L) and were not acutely toxic in primary cells. Example 2 RNA encoding F(iii), F(i), F(ii) and DS-Cav1 was administered to mice as set out in the Materials and Methods section. Figure 2 displays the RSV pre-F IgG binding antibody geometric mean titres on day 21 (3wp1) and day 35 (2wp2) in animals immunized with either 2 μg (Figure 2A) or 0.2 μg (Figure 2B) of RNA encoding F(iii), F(ii), F(i) or DS-Cav1 (where each point represents an individual animal). There were no binding antibody responses in the saline control group (data not shown). On day 21, all constructs elicited measurable pre-F-specific IgG binding antibodies with a 2μg dose. A single dose of DS-Cav1 elicited lower pre-F-specific IgG binding antibodies compared to the other constructs. On day 35, F(i) elicited the highest response at both doses, compared to the other constructs. Figure 3 displays the RSV A neutralizing antibody titres (ED60) on day 21 (3wp1) and day 35 (2wp2) in animals immunized with either (Figure 3A) 2 μg or (Figure 3B) 0.2 μg of RNA encoding F(iii), F(i), F(ii), or DS-Cav1 (where each point represents an individual animal). The saline group did not generate a measurable neutralization response to RSV A (data not shown). At the high (2μg) dose, one vaccination generated measurable neutralization to RSV A. DS-Cav1 vaccination generated the lowest neutralization titres with one dose (Figure 3B). All neutralization titres were boosted with a second vaccination. On day 35, F(i) elicited the highest neutralization titres at both doses, compared to the other constructs. Example 3 – Toluene nitrosulphonic acid (TNS) fluorescence assay for determining pKa Steps (1) – (14): (1) admixing 400 μL of 2 mM of the cationic lipid that is in 100 volume % ethanol and 800 μL of 0.3 mM of fluorescent probe TNS, which is in 90 volume % ethanol and 10 volume % methanol, thereby obtaining a lipid/TNS mixture; (2) admixing 7.5 μL of the lipid/TNS mixture and 242.5 μL of a first buffer comprising a sodium salt buffer comprising 20 mM sodium phosphate, 25 mM sodium citrate, 20 mM sodium acetate, and 150 mM sodium chloride, wherein the first buffer has a first pH from 4.44 to 4.52, thereby obtaining a first mixture, and dispensing 100 μL of the first mixture in a first well of a 96-well plate, which has a clear bottom; Docket No: 70330WO01 (3) admixing 7.5 μL of the lipid/TNS mixture and 242.5 μL of a second buffer comprising the sodium salt buffer, wherein the second buffer has a second pH of 5.27, thereby obtaining a second mixture, and dispensing 100 μL of the second mixture in a second well of the 96-well plate; (4) admixing 7.5 μL of the lipid/TNS mixture and 242.5 μL of a third buffer comprising the sodium salt buffer, wherein the third buffer has a third pH of from 6.15 to 6.21, thereby obtaining a third mixture, and dispensing 100 μL of the third mixture in a third well of the 96-well plate; (5) admixing 7.5 μL of the lipid/TNS mixture and 242.5 μL of a fourth buffer comprising the sodium salt buffer, wherein the fourth buffer has a fourth pH of 6.57, thereby obtaining a fourth mixture, and dispensing 100 μL of the fourth mixture in a fourth well of the 96-well plate; (6) admixing 7.5 μL of the lipid/TNS mixture and 242.5 μL of a fifth buffer comprising the sodium salt buffer, wherein the fifth buffer has a fifth pH of from 7.10 to 7.20, thereby obtaining a fifth mixture, and dispensing 100 μL of the fifth mixture in a fifth well of the 96-well plate; (7) admixing 7.5 μL of the lipid/TNS mixture and 242.5 μL of a sixth comprising the sodium salt buffer, wherein the sixth buffer has a sixth pH of from 7.72 to 7.80, thereby obtaining a sixth mixture, and dispensing 100 μL of the sixth mixture in a sixth well of the 96-well plate; (8) admixing 7.5 μL of the lipid/TNS mixture and 242.5 μL of a seventh buffer comprising the sodium salt buffer, wherein the seventh buffer has a seventh pH of from 8.27 to 8.33, thereby obtaining a seventh mixture, and dispensing 100 μL of the seventh mixture in a seventh well of the 96-well plate; (9) admixing 7.5 μL of the lipid/TNS mixture and 242.5 μL of an eighth buffer comprising the sodium salt buffer, wherein the eighth buffer has an eighth pH of from 10.47 to 11.12, thereby obtaining an eighth mixture, and dispensing 100 μL of the eighth mixture in an eighth well of the 96-well plate; (10) measuring the absolute fluorescence at a wavelength of 431 nm with an excitation wavelength of 322 nm and a cut-off below 420 nm of each of the first through eighth wells and an empty well of the 96-well plate; (11) subtracting the absolute fluorescence of the empty well from each of the absolute fluorescence values of the first through the eighth wells, thereby obtaining a blank-subtracted fluorescence for each of the first through eighth mixtures; (12) normalising each of the blank-subtracted fluorescence values of the first through eighth mixtures to the blank-subtracted fluorescence of the first mixture, thereby obtaining a relative fluorescence for each of the first through eighth mixtures, the relative fluorescence of the first mixture being 1; Docket No: 70330WO01 (13) regressing by the Henderson-Hasselbalch equation, the first through eighth pH values versus the respective relative fluorescence values of the first through eighth mixtures thereby obtaining a line of best fit; and (14) determining the pKa as the pH at which a relative fluorescence of 0.5 is obtained on the line of best fit. Example 4 RNA encoding F(i), F(ii), F(iii) or DS-Cav1 was administered to mice as set out in the Materials and Methods section. Figure 4A presents the RSV A neutralising antibody titres (ED60) on day 21 (3wp1) and day 35 (2wp2) in animals immunized with 0.5 μg of F(i), F(ii), F(iii) or DS-Cav1 (where each point represents an individual animal). The saline group did not generate a measurable neutralisation response to RSV A (data not shown). The neutralisation titres elicited from F(i) were higher than F(ii), F(iii) and DS-Cav1, at both day 21 and day 35.. Figure 4B presents the RSV A and B day 35 (2wp2) cross-neutralisation titres to lab-adapted (RSV A-long and RSV B-18537) and clinical RSV strains (RSV A-Clinical 2015, RSV B-Clinical 2015 and 2017). Cross-neutralising antibody titres elicited from F(i) were generally higher than F(ii), F(iii) and DS-Cav1. Figure 5A presents the pre-F IgG binding antibody titres on day 21 and day 35.

Docket No: 70330WO01 SEQUENCES SEQ ID NO: 1: Amino acid (AA) sequence of wild-type RSV-F (A2 strain) containing substitutions K66E and Q101P relative to GenBank Accession number KT992094 with full cytoplasmic tail. SEQ ID NO: 1 is herein referred to as “wild-type”. MELLILKANAITTILTAVTFCFASGQNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKEN KCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRK RRFLGFLLGVGSAIASGVAVSKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTSKVLDLKNYIDK QLLPIVNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITN DQKKLMSNNVQIVRQQSYSIMSIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLT RTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDV SSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYV KGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRKSDELLHNVNAGKSTTNIMITTIIIVIIV ILLSLIAVGLLLYCKARSTPVTLSKDQLSGINNIAFSN SEQ ID NO: 2: AA sequence of wild-type RSV-F B subtype strain 18537 (Uniprot ID: P13843) with full cytoplasmic tail. SEQ ID NO: 2 is herein referred to as “wild-type”. MELLIHRSSAIFLTLAVNALYLTSSQNITEEFYQSTCSAVSRGYFSALRTGWYTSVITIELSNIKET KCNGTDTKVKLIKQELDKYKNAVTELQLLMQNTPAANNRARREAPQYMNYTINTTKNLNVSISKKRK RRFLGFLLGVGSAIASGIAVSKVLHLEGEVNKIKNALLSTNKAVVSLSNGVSVLTSKVLDLKNYINN RLLPIVNQQSCRISNIETVIEFQQMNSRLLEITREFSVNAGVTTPLSTYMLTNSELLSLINDMPITN DQKKLMSSNVQIVRQQSYSIMSIIKEEVLAYVVQLPIYGVIDTPCWKLHTSPLCTTNIKEGSNICLT RTDRGWYCDNAGSVSFFPQADTCKVQSNRVFCDTMNSLTLPSEVSLCNTDIFNSKYDCKIMTSKTDI SSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKLEGKNLYV KGEPIINYYDPLVFPSDEFDASISQVNEKINQSLAFIRRSDELLHNVNTGKSTTNIMITTIIIVIIV VLLSLIAIGLLLYCKAKNTPVTLSKDQLSGINNIAFSK SEQ ID NO: 3: AA sequence of F(i) construct MELLILKANAITTILTAVTFCFASGQNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKEN KCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPACNNRARRELPRFMNYTLNNAKKTNVTLSKKRK RRFLGFLLGVGSACASGVAVSKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTIKVLDLKNYIDK QLLPIVNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITN DQKKLMSNNVQIVRQQSYSIMSIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLT RTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDV SSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYV KGEPIINFYDPLVFPSSEFDASISQVNEKINQSLAFIRKSDELLHNVNAGKSTTNIMITTIIIVIIV ILLSLIAVGLLLYCKARSTPVTLSKDQLSGINNIAFSN SEQ ID NO: 4: RNA sequence of construct KM173 (encoding F(i)) – all U ribonucleotides are 1mΨ – GC content 48.00% – 5’ and 3’ UTRs are “UTR4” AGGAGAAGCUGUCUAUCGGGCUCCAGCGGUCAUGGAGCUGCUGAUCCUGAAAGCCAACGCCAUUACA ACCAUUCUGACCGCCGUGACCUUUUGCUUCGCCAGCGGCCAGAACAUUACCGAAGAGUUCUACCAGU CCACCUGCUCCGCCGUGUCUAAAGGCUACCUGUCCGCCCUGAGAACCGGAUGGUACACAAGCGUGAU CACCAUCGAACUGAGCAACAUCAAGGAAAAUAAGUGCAACGGGACAGACGCCAAGGUGAAACUGAUC AAGCAGGAGCUGGAUAAGUACAAGAACGCCGUGACAGAGCUGCAGCUGCUGAUGCAGUCUACACCAG Docket No: 70330WO01 CCUGCAAUAACCGCGCCCGGCGCGAACUGCCACGGUUCAUGAAUUAUACCCUGAACAAUGCCAAGAA AACAAAUGUGACACUGUCUAAGAAACGCAAGCGGAGAUUUCUGGGGUUCCUGCUGGGCGUGGGCAGC GCCUGCGCCAGCGGCGUGGCCGUGAGCAAAGUGCUGCAUCUGGAAGGCGAGGUGAACAAGAUCAAGU CUGCCCUGCUGUCCACAAACAAGGCCGUGGUGUCUCUGAGCAACGGGGUGUCUGUGCUGACAAUUAA GGUGCUGGAUCUGAAAAAUUAUAUUGAUAAACAGCUGCUGCCAAUUGUGAACAAGCAGAGCUGCUCC AUCUCCAACAUUGAGACCGUGAUUGAGUUUCAGCAGAAAAAUAAUAGGCUGCUGGAGAUUACCAGAG AGUUCAGCGUGAACGCCGGGGUGACCACACCAGUGUCUACAUACAUGCUGACCAACUCCGAGCUGCU GAGCCUGAUUAACGACAUGCCCAUCACAAACGAUCAGAAGAAACUGAUGUCUAACAAUGUGCAGAUU GUGCGGCAGCAGUCUUACUCCAUCAUGAGCAUUAUCAAGGAGGAAGUGCUGGCCUACGUGGUGCAGC UGCCUCUGUAUGGGGUGAUCGACACCCCUUGUUGGAAGCUGCACACAUCUCCACUGUGCACAACCAA CACCAAGGAAGGAAGCAAUAUCUGUCUGACAAGAACCGACAGAGGCUGGUACUGCGACAAUGCCGGG UCCGUGAGCUUCUUUCCCCAGGCCGAGACCUGCAAGGUGCAGUCCAACAGGGUGUUUUGCGAUACAA UGAAUAGCCUGACCCUGCCCUCCGAGGUGAACCUGUGUAACGUGGAUAUCUUCAACCCAAAGUAUGA UUGCAAAAUCAUGACCAGCAAGACCGACGUGAGCUCUAGCGUGAUUACAUCUCUGGGCGCCAUUGUG AGCUGUUAUGGAAAGACAAAGUGUACCGCCUCCAACAAGAAUAGAGGCAUCAUUAAGACCUUCAGCA ACGGAUGUGACUAUGUGUCCAAUAAAGGCGUGGACACAGUGUCUGUGGGGAACACCCUGUACUAUGU GAACAAGCAGGAAGGCAAGAGCCUGUACGUGAAGGGGGAGCCCAUCAUUAAUUUCUACGAUCCCCUG GUGUUUCCUUCCAGCGAAUUCGAUGCCUCCAUCUCCCAGGUGAACGAAAAGAUCAAUCAGAGCCUGG CCUUUAUCAGAAAGAGCGAUGAACUGCUGCAUAAUGUGAAUGCCGGCAAAUCCACCACAAACAUUAU GAUUACCACAAUCAUUAUCGUGAUCAUUGUGAUUCUGCUGUCUCUGAUUGCCGUGGGGCUGCUGCUG UAUUGCAAAGCCAGGUCCACACCUGUGACCCUGUCUAAGGAUCAGCUGUCUGGGAUUAACAAUAUCG CCUUUUCCAACUGAUAAGCCGCCGCUCCAGCUUUGCACGUUUCGAUCCCAAAGGCCCUUUUUAGGGC CGACCAUUCAUUGCAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGCAUAUGACUAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAA SEQ ID NO: 5: AM14 light chain AA sequence METPAELLFLLLLWLPDTTGDIQMTQSPSSLSASVGDRVTITCQASQDIKKYLNWYHQKPGKVPELL MHDASNLETGVPSRFSGRGSGTDFTLTISSLQPEDIGTYYCQQYDNLPPLTFGGGTKVEIKRTVAAP SVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLT LSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC SEQ ID NO: 6: AM14 heavy chain AA sequence MEFGLSWVFLVAILEGVHCEVQLVESGGGVVQPGRSLRLSCAASGFSFSHYAMHWVRQAPGKGLEWV AVISYDGENTYYADSVKGRFSISRDNSKNTVSLQMNSLRPEDTALYYCARDRIVDDYYYYGMDVWGQ GATVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQS SGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLF PPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLH QDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDI AVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLS PGK SEQ ID NO: 7: D25 light chain AA sequence METPAELLFLLLLWLPDTTGDIQMTQSPSSLSAAVGDRVTITCQASQDIVNYLNWYQQKPGKAPKLL IYVASNLETGVPSRFSGSGSGTDFSLTISSLQPEDVATYYCQQYDNLPLTFGGGTKVEIKRTVAAPS Docket No: 70330WO01 VFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTL SKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC SEQ ID NO: 8: D25 heavy chain AA sequence MEFGLSWVFLVAILEGVHCQVQLVQSGAEVKKPGSSVMVSCQASGGPLRNYIINWLRQAPGQGPEWM GGIIPVLGTVHYAPKFQGRVTITADESTDTAYIHLISLRSEDTAMYYCATETALVVSTTYLPHYFDN WGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAV LQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSV FLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLT VLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYP SDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSL SLSPGK SEQ ID NO: 9: Motavizumab light chain AA sequence METPAELLFLLLLWLPDTTGDIQMTQSPSTLSASVGDRVTITCSASSRVGYMHWYQQKPGKAPKLLI YDTSKLASGVPSRFSGSGSGTEFTLTISSLQPDDFATYYCFQGSGYPFTFGGGTKVEIKRTVAAPSV FIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLS KADYEKHKVYACEVTHQGLSSPVTKSFNRGEC SEQ ID NO: 10: Motavizumab heavy chain AA sequence MEFGLSWVFLVAILEGVHCQVTLRESGPALVKPTQTLTLTCTFSGFSLSTAGMSVGWIRQPPGKALE WLADIWWDDKKHYNPSLKDRLTISKDTSKNQVVLKVTNMDPADTATYYCARDMIFNFYFDVWGQGTT VTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGL YSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPK PKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDW LNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVE WESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK SEQ ID NO: 11: AA sequence of exemplary F2-F1 linker sequence GSGSG SEQ ID NO: 12: AA sequence of exemplary F2-F1 linker sequence GSGSGRS SEQ ID NO: 13: AA sequence of exemplary F2-F1 linker sequence GS SEQ ID NO: 14: AA sequence of exemplary F2-F1 linker sequence GSGSGR SEQ ID NO: 15: AA sequence of DS-CAV1 Docket No: 70330WO01 MELLILKANAITTILTAVTFCFASGQNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKEN KCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRK RRFLGFLLGVGSAIASGVAVCKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTFKVLDLKNYIDK QLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITN DQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLT RTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDV SSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYV KGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRKSDELLHNVNAGKSTTNIMITTIIIVIIV ILLSLIAVGLLLYCKARSTPVTLSKDQLSGINNIAFSN SEQ ID NO: 16: AA sequence of F(ii) construct MELLILKANAITTILTAVTFCFASGQNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKEI KCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATNNRARRELPRFMNYTLNNAKKTNVTLSKKRK RRFLGFLLGVGSAIASGVAVSKVLHLEGEVNKIKSALLSTNKAVVSLSNGVSVLTSKVLDLKNYIDK QLLPIVNKQSCSIPNIETVIEFQQKNNRLLEITREFSVNAGVTTPVSTYMLTNSELLSLINDMPITN DQKKLMSNNVQIVRQQSYSIMSIIKEEVLAYVVQLPLYGVIDTPCWKLHTSPLCTTNTKEGSNICLT RTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSLTLPSEVNLCNVDIFNPKYDCKIMTSKTDV SSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDYVSNKGVDTVSVGNTLYYVNKQEGKSLYV KGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRKSDELLHNVNAGKSTTNIMITTIIIVIIV ILLSLIAVGLLLYCKARSTPVTLSKDQLSGINNIAFSN SEQ ID NO: 17: AA sequence of F(iii) construct MELLILKANAITTILTAVTFCFASGQNITEEFYQSTCSAVSKGYLSALRTGWYTSVITIELSNIKEN KCNGTDAKVKLIKQELDKYKNAVTELQLLMQSTPATGSGSAICSGVAVCKVLHLEGEVNKIKSALLS TNKAVVSLSNGVSVLTFKVLDLKNYIDKQLLPILNKQSCSISNIETVIEFQQKNNRLLEITREFSVN AGVTTPVSTYMLTNSELLSLINDMPITNDQKKLMSNNVQIVRQQSYSIMCIIKEEVLAYVVQLPLYG VIDTPCWKLHTSPLCTTNTKEGSNICLTRTDRGWYCDNAGSVSFFPQAETCKVQSNRVFCDTMNSRT LPSEVNLCNVDIFNPKYDCKIMTSKTDVSSSVITSLGAIVSCYGKTKCTASNKNRGIIKTFSNGCDY VSNKGVDTVSVGNTLYCVNKQEGKSLYVKGEPIINFYDPLVFPSDEFDASISQVNEKINQSLAFIRK SDELLHNVNAGKSTTNIMITTIIIVIIVILLSLIAVGLLLY SEQ ID NO: 18: RNA sequence of 5’ UTR of “UTR4” (HIST2H4A 5’ UTR) – n.b., spacing to be ignored (sequence to be read as one continuous sequence) AGGAGAAGCU GUCUAUCGGG CUCCAGCGGU C SEQ ID NO: 19: RNA sequence of 3’ UTR of “UTR4” (HIST2H4A 3’ UTR) – n.b., spacing to be ignored (sequence to be read as one continuous sequence) GCCGCCGCUC CAGCUUUGCA CGUUUCGAUC CCAAAGGCCC UUUUUAGGGC CGACCA SEQ ID NO: 20: RNA sequence of possible 5’ UTR GAGAAUAAACUAGUAUUCUUCUGGUCCCCACAGACUCAGAGAGAACCCGCCACC SEQ ID NO: 21: RNA sequence of possible 3’ UTR Docket No: 70330WO01 CUCGAGCUGGUACUGCAUGCACGCAAUGCUAGCUGCCCCUUUCCCGUCCUGGGUACCCCGAGUCUCC CCCGACCUCGGGUCCCAGGUAUGCUCCCACCUCCACCUGCCCCACUCACCACCUCUGCUAGUUCCAG ACACCUCCCAAGCACGCAGCAAUGCAGCUCAAAACGCUUAGCCUAGCCACACCCCCACGGGAAACAG CAGUGAUUAACCUUUAGCAAUAAACGAAAGUUUAACUAAGCUAUACUAACCCCAGGGUUGGUCAAUU UCGUGCCAGCCACACCCUGGAGCUAGC SEQ ID NO: 22: RNA sequence of construct KM135 (encoding F(ii)) – all U ribonucleotides are 1mΨ – GC content 48.90% – 5’ and 3’ UTRs are “UTR4” AGGAGAAGCUGUCUAUCGGGCUCCAGCGGUCAUGGAGCUGCUGAUCCUGAAAGCCAACGCCAUUACAACCAUUC UGACCGCCGUGACCUUUUGCUUCGCCAGCGGCCAGAACAUUACCGAAGAGUUCUACCAGUCCACCUGCUCCGCC GUGUCUAAAGGCUACCUGUCCGCCCUGAGAACCGGAUGGUACACAAGCGUGAUCACCAUCGAACUGAGCAACAU CAAGGAAAUUAAGUGCAAUGGGACAGACGCCAAGGUGAAACUGAUCAAGCAGGAGCUGGAUAAGUACAAGAACG CCGUGACAGAGCUGCAGCUGCUGAUGCAGUCUACACCAGCCACCAAUAACCGCGCCCGGCGCGAACUGCCACGG UUCAUGAAUUAUACCCUGAACAAUGCCAAGAAAACAAAUGUGACACUGUCUAAGAAACGCAAGCGGAGAUUUCU GGGGUUCCUGCUGGGCGUGGGCAGCGCCAUUGCCAGCGGCGUGGCCGUGAGCAAAGUGCUGCAUCUGGAAGGCG AGGUGAACAAGAUCAAGUCUGCCCUGCUGUCCACAAACAAGGCCGUGGUGUCUCUGAGCAACGGGGUGUCUGUG CUGACAUCUAAGGUGCUGGAUCUGAAAAAUUAUAUUGAUAAACAGCUGCUGCCAAUUGUGAACAAGCAGAGCUG CUCCAUCCCCAACAUUGAGACCGUGAUUGAGUUUCAGCAGAAAAAUAACAGGCUGCUGGAGAUUACCAGAGAGU UCAGCGUGAACGCCGGGGUGACCACACCAGUGUCUACAUACAUGCUGACCAACUCCGAGCUGCUGAGCCUGAUU AACGACAUGCCCAUCACAAACGAUCAGAAGAAACUGAUGUCUAACAAUGUGCAGAUUGUGCGGCAGCAGUCUUA CUCCAUCAUGAGCAUUAUCAAGGAGGAAGUGCUGGCCUACGUGGUGCAGCUGCCUCUGUAUGGGGUGAUCGACA CCCCUUGUUGGAAGCUGCACACAUCUCCACUGUGCACAACCAACACCAAGGAAGGAAGCAAUAUCUGUCUGACA AGAACCGACAGAGGCUGGUACUGCGACAAUGCCGGGUCCGUGAGCUUCUUUCCCCAGGCCGAGACCUGCAAGGU GCAGUCCAACAGGGUGUUUUGCGAUACAAUGAAUAGCCUGACCCUGCCCUCCGAGGUGAACCUGUGUAACGUGG AUAUCUUCAACCCAAAGUAUGAUUGCAAAAUCAUGACCAGCAAGACCGACGUGAGCUCUAGCGUGAUUACAUCU CUGGGCGCCAUUGUGAGCUGUUAUGGAAAGACAAAGUGUACCGCCUCCAACAAGAAUAGAGGCAUCAUUAAGAC CUUCAGCAACGGAUGUGACUAUGUGUCCAAUAAAGGCGUGGACACAGUGUCUGUGGGGAACACCCUGUACUAUG UGAACAAGCAGGAAGGCAAGAGCCUGUACGUGAAGGGGGAGCCCAUCAUUAAUUUCUACGAUCCCCUGGUGUUU CCUUCCGACGAAUUCGAUGCCUCCAUCUCCCAGGUGAACGAAAAGAUCAAUCAGAGCCUGGCCUUUAUCAGAAA GAGCGAUGAACUGCUGCAUAAUGUGAAUGCCGGCAAAUCCACCACAAACAUUAUGAUUACCACAAUCAUUAUCG UGAUCAUUGUGAUUCUGCUGUCUCUGAUUGCCGUGGGGCUGCUGCUGUAUUGCAAAGCCAGGUCCACACCUGUG ACCCUGUCUAAGGAUCAGCUGUCUGGGAUUAACAAUAUCGCCUUUUCCAACUAAUAGCCGCCGCUCCAGCUUUG CACGUUUCGAUCCCAAAGGCCCUUUUUAGGGCCGACCAUUUUCAUUGCGCGCGCAGGCAUUGCAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAGCAUAUGACUAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAA SEQ ID NO: 23: RNA sequence of construct KM03 (encoding DS-Cav1) – all U ribonucleotides are 1mΨ – GC content 49.50% – 5’ and 3’ UTRs are “UTR4” AGGAGAAGCUGUCUAUCGGGCUCCAGCGGUCAUGGAGCUGCUGAUCCUGAAAGCCAACGCCAUUACAACCAUUCUGA CCGCCGUGACCUUUUGCUUCGCCAGCGGCCAGAACAUUACCGAAGAGUUCUACCAGUCCACCUGCUCCGCCGUGUCU AAAGGCUACCUGUCCGCCCUGAGAACCGGAUGGUACACAAGCGUGAUCACCAUCGAACUGAGCAACAUCAAGGAAAA UAAGUGCAAUGGGACAGACGCCAAGGUGAAACUGAUCAAGCAGGAGCUGGAUAAGUACAAGAACGCCGUGACAGAGC UGCAGCUGCUGAUGCAGUCUACACCAGCCACCAAUAACCGCGCCCGGCGCGAACUGCCACGGUUCAUGAAUUAUACC CUGAACAAUGCCAAGAAAACAAAUGUGACACUGUCUAAGAAACGCAAGCGGAGAUUUCUGGGGUUCCUGCUGGGCGU GGGCAGCGCCAUUGCCAGCGGCGUGGCCGUGUGCAAAGUGCUGCAUCUGGAAGGCGAGGUGAACAAGAUCAAGUCUG CCCUGCUGUCCACAAACAAGGCCGUGGUGUCUCUGAGCAACGGGGUGUCUGUGCUGACAUUUAAGGUGCUGGAUCUG AAAAAUUAUAUUGAUAAACAGCUGCUGCCAAUUCUGAACAAGCAGAGCUGCUCCAUCUCCAACAUUGAGACCGUGAU UGAGUUUCAGCAGAAAAAUAACAGGCUGCUGGAGAUUACCAGAGAGUUCAGCGUGAACGCCGGGGUGACCACACCAG UGUCUACAUACAUGCUGACCAACUCCGAGCUGCUGAGCCUGAUUAACGACAUGCCCAUCACAAACGAUCAGAAGAAA CUGAUGUCUAACAAUGUGCAGAUUGUGCGGCAGCAGUCUUACUCCAUCAUGUGCAUUAUCAAGGAGGAAGUGCUGGC CUACGUGGUGCAGCUGCCUCUGUAUGGGGUGAUCGACACCCCUUGUUGGAAGCUGCACACAUCUCCACUGUGCACAA Docket No: 70330WO01 CCAACACCAAGGAAGGAAGCAAUAUCUGUCUGACAAGAACCGACAGAGGCUGGUACUGCGACAAUGCCGGGUCCGUG AGCUUCUUUCCCCAGGCCGAGACCUGCAAGGUGCAGUCCAACAGGGUGUUUUGCGAUACAAUGAAUAGCCUGACCCU GCCCUCCGAGGUGAACCUGUGUAACGUGGAUAUCUUCAACCCAAAGUAUGAUUGCAAAAUCAUGACCAGCAAGACCG ACGUGAGCUCUAGCGUGAUUACAUCUCUGGGCGCCAUUGUGAGCUGUUAUGGAAAGACAAAGUGUACCGCCUCCAAC AAGAAUAGAGGCAUCAUUAAGACCUUCAGCAACGGAUGUGACUAUGUGUCCAAUAAAGGCGUGGACACAGUGUCUGU GGGGAACACCCUGUACUAUGUGAACAAGCAGGAAGGCAAGAGCCUGUACGUGAAGGGGGAGCCCAUCAUUAAUUUCU ACGAUCCCCUGGUGUUUCCUUCCGACGAAUUCGAUGCCUCCAUCUCCCAGGUGAACGAAAAGAUCAAUCAGAGCCUG GCCUUUAUCAGAAAGAGCGAUGAACUGCUGCAUAAUGUGAAUGCCGGCAAAUCCACCACAAACAUUAUGAUUACCAC AAUCAUUAUCGUGAUCAUUGUGAUUCUGCUGUCUCUGAUUGCCGUGGGGCUGCUGCUGUAUUGCAAAGCCAGGUCCA CACCUGUGACCCUGUCUAAGGAUCAGCUGUCUGGGAUUAACAAUAUCGCCUUUUCCAACUAGGCCGCCGCUCCAGCU UUGCACGUUUCGAUCCCAAAGGCCCUUUUUAGGGCCGACCAUUAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAA SEQ ID NO: 24: RNA sequence of construct KM126 (encoding F(iii) construct (including full deletion of CT)) – all U ribonucleotides are 1mΨ – GC content 56.40% ^{AGGGAAAUAAGAGAGAAAAGAAGAGUAAGAAGAAAUAUAAGAGCCACCAUGGAGCUGCUGAUCCUGAAGGCCAACGC} CAUCACGACCAUCCUGACCGCCGUGACCUUCUGCUUCGCCAGCGGGCAGAACAUCACCGAGGAGUUCUACCAGUCCA CCUGCUCCGCCGUGAGCAAGGGCUACCUGUCUGCCCUGAGAACCGGCUGGUACACCAGCGUGAUCACCAUCGAGCUG UCCAACAUCAAGGAGAACAAGUGCAACGGCACCGACGCCAAGGUGAAGCUGAUCAAGCAGGAGCUGGACAAGUACAA GAACGCAGUGACCGAGCUGCAGCUGCUGAUGCAGAGCACACCAGCCACCGGUAGCGGGUCCGCCAUUUGCUCCGGCG UGGCCGUGUGCAAGGUGCUGCACCUGGAGGGCGAGGUGAACAAGAUCAAGAGCGCCCUGCUCUCCACCAACAAGGCC GUGGUGAGCCUGAGCAACGGGGUGAGCGUGCUGACCUUCAAGGUGCUGGACCUGAAGAACUACAUCGACAAGCAGCU GCUGCCUAUCCUGAACAAGCAGAGCUGCAGCAUCAGCAACAUCGAGACCGUGAUCGAGUUCCAGCAGAAGAACAACC GGCUGCUGGAGAUCACCAGGGAGUUCAGCGUGAACGCAGGGGUGACCACACCCGUGUCCACCUACAUGCUGACCAAC UCCGAGCUGCUGAGCCUGAUCAACGAUAUGCCCAUCACCAACGACCAGAAGAAGCUGAUGAGCAACAACGUGCAGAU CGUGCGGCAGCAGUCCUACUCCAUCAUGUGCAUCAUCAAGGAGGAGGUGCUGGCCUACGUGGUGCAGCUGCCCCUGU ACGGCGUGAUCGACACCCCUUGCUGGAAGCUGCACACCAGCCCUCUGUGCACCACCAACACGAAGGAGGGCAGCAAU AUCUGCCUGACCCGGACCGACAGGGGCUGGUACUGCGACAACGCCGGCAGCGUGUCCUUCUUUCCCCAGGCCGAGAC CUGCAAGGUGCAGUCCAACAGGGUGUUCUGCGACACCAUGAACUCUCGCACCCUGCCCAGCGAGGUGAACCUGUGCA ACGUGGACAUCUUCAACCCCAAGUACGACUGCAAGAUCAUGACCUCCAAGACCGACGUGUCCUCUAGCGUUAUCACC UCCCUGGGCGCCAUCGUGAGCUGCUACGGCAAGACCAAGUGCACCGCCAGCAACAAGAACAGGGGCAUCAUCAAGAC CUUCAGCAACGGGUGCGACUACGUGUCCAACAAGGGCGUGGACACCGUGUCCGUGGGCAACACCCUGUACUGCGUGA ACAAGCAGGAGGGCAAGAGCCUGUACGUGAAGGGCGAGCCCAUCAUCAACUUCUACGACCCUCUGGUGUUCCCCAGC GACGAGUUCGACGCCAGCAUCUCCCAGGUGAACGAGAAGAUCAACCAGAGCCUGGCCUUCAUCCGCAAGAGCGACGA GCUGCUGCACAACGUGAACGCCGGCAAGAGCACCACAAACAUCAUGAUCACCACCAUCAUCAUCGUGAUAAUCGUGA UCCUGCUGUCCCUGAUCGCUGUGGGCCUGCUGCUGUACUGAUAAUAGGCUGGAGCCUCGGUGGCCAUGCUUCUUGCC CCUUGGGCCUCCCCCCAGCCCCUCCUCCCCUUCCUGCACCCGUACCCCCGUGGUCUUUGAAUAAAGUCUGAGUGGGC GGCUUAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA SEQ ID NO: 25: RNA sequence of construct XW02 (encoding DS-Cav1 construct used in in vivo study) – all U ribonucleotides are 1mΨ – GC content 49.40%% AGGAGAAGCUGUCUAUCGGGCUCCAGCGGUCAUGGAGCUGCUGAUCCUGAAAGCCAACGCCAUUACAACCAUUC UGACCGCCGUGACCUUUUGCUUCGCCAGCGGCCAGAACAUUACCGAAGAGUUCUACCAGUCCACCUGCUCCGCC GUGUCUAAAGGCUACCUGUCCGCCCUGAGAACCGGAUGGUACACAAGCGUGAUCACCAUCGAACUGAGCAACAU CAAGGAAAAUAAGUGCAAUGGGACAGACGCCAAGGUGAAACUGAUCAAGCAGGAGCUGGAUAAGUACAAGAACG CCGUGACAGAGCUGCAGCUGCUGAUGCAGUCUACACCAGCCACCAAUAACCGCGCCCGGCGCGAACUGCCACGG UUCAUGAAUUAUACCCUGAACAAUGCCAAGAAAACAAAUGUGACACUGUCUAAGAAACGCAAGCGGAGAUUUCU GGGGUUCCUGCUGGGCGUGGGCAGCGCCAUUGCCAGCGGCGUGGCCGUGUGCAAAGUGCUGCAUCUGGAAGGCG AGGUGAACAAGAUCAAGUCUGCCCUGCUGUCCACAAACAAGGCCGUGGUGUCUCUGAGCAACGGGGUGUCUGUG CUGACAUUUAAGGUGCUGGAUCUGAAAAAUUAUAUUGAUAAACAGCUGCUGCCAAUUCUGAACAAGCAGAGCUG CUCCAUCUCCAACAUUGAGACCGUGAUUGAGUUUCAGCAGAAAAAUAACAGGCUGCUGGAGAUUACCAGAGAGU UCAGCGUGAACGCCGGGGUGACCACACCAGUGUCUACAUACAUGCUGACCAACUCCGAGCUGCUGAGCCUGAUU AACGACAUGCCCAUCACAAACGAUCAGAAGAAACUGAUGUCUAACAAUGUGCAGAUUGUGCGGCAGCAGUCUUA Docket No: 70330WO01 CUCCAUCAUGUGCAUUAUCAAGGAGGAAGUGCUGGCCUACGUGGUGCAGCUGCCUCUGUAUGGGGUGAUCGACA CCCCUUGUUGGAAGCUGCACACAUCUCCACUGUGCACAACCAACACCAAGGAAGGAAGCAAUAUCUGUCUGACA AGAACCGACAGAGGCUGGUACUGCGACAAUGCCGGGUCCGUGAGCUUCUUUCCCCAGGCCGAGACCUGCAAGGU GCAGUCCAACAGGGUGUUUUGCGAUACAAUGAAUAGCCUGACCCUGCCCUCCGAGGUGAACCUGUGUAACGUGG AUAUCUUCAACCCAAAGUAUGAUUGCAAAAUCAUGACCAGCAAGACCGACGUGAGCUCUAGCGUGAUUACAUCU CUGGGCGCCAUUGUGAGCUGUUAUGGAAAGACAAAGUGUACCGCCUCCAACAAGAAUAGAGGCAUCAUUAAGAC CUUCAGCAACGGAUGUGACUAUGUGUCCAAUAAAGGCGUGGACACAGUGUCUGUGGGGAACACCCUGUACUAUG UGAACAAGCAGGAAGGCAAGAGCCUGUACGUGAAGGGGGAGCCCAUCAUUAAUUUCUACGAUCCCCUGGUGUUU CCUUCCGACGAAUUCGAUGCCUCCAUCUCCCAGGUGAACGAAAAGAUCAAUCAGAGCCUGGCCUUUAUCAGAAA GAGCGAUGAACUGCUGCAUAAUGUGAAUGCCGGCAAAUCCACCACAAACAUUAUGAUUACCACAAUCAUUAUCG UGAUCAUUGUGAUUCUGCUGUCUCUGAUUGCCGUGGGGCUGCUGCUGUAUUGCAAAGCCAGGUCCACACCUGUG ACCCUGUCUAAGGAUCAGCUGUCUGGGAUUAACAAUAUCGCCUUUUCCAACUAGCCGCCGCUCCAGCUUUGCAC GUUUCGAUCCCAAAGGCCCUUUUUAGGGCCGACCAUUUUCAUUGCGCGCGCAGGCAUUGCAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAGCAUAUGACUAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA [1] Rha et al. Pediatrics.2020 Jul;146(1):e20193611 [2] Falsey et al. N Engl J Med.2005 Apr 28;352(17):1749-59. [3] Falsey and Walsh. Clin Microbiol Rev.2000;13:371–84. [4] Groothuis et al. Adv Ther 2011;28:110-25. [5] Feltes et al. Pediatr Res 2011; 70:186-91. [6] Carbonell-Estrany et al. Pediatrics 2010;125:e35–51. [7] O’Brien et al. Lancet Infect Dis 2015;15:1398-408. [8] The IMpact-RSV study group. Pediatrics 1998;102:531-537. [9] Krarup et al. Nat Commun.2015 Sep 3;6:8143. [10] https://www.gsk.com/en-gb/media/press-releases/gsk-s-older-adult-respiratory-syncytial-virus- rsv-vaccine-candidate/ [11] Whitehead et al. Journal of Virology.1998;72(5) [12] Sievers et al. Methods Mol Biol.2014;1079:105-16. [13] Gilman et al. PLOSPathogens.2015; 11(7), e1005035 [14] McLellan et al. Science.2013.340, 6136.1113-7 [15] WO 2005/113782 [16] Chen et al. Mol Cell.201976, 1: 96-109 [17] Edgar. BMC Bioinformatics.2004.5, 113 [18] Edgar et al. bioRxiv.2021.06.20.449169 [19] WO 2012/006380 [20] US20100324120 [21] WO 2021/038508 [22] Gennaro. 2000. Remington: The Science and Practice of Pharmacy. 20th edition, ISBN: 0683306472. [23] van Drunnen Little-van den Hurk et al. Rev Med Virol.2007.17(1): 5-34 [24] Aw et al. Immunology.2007.120(4): 435-46

Claims

Docket No: 70330WO01 CLAIMS 1. A recombinant ribonucleic acid (RNA) encoding a respiratory syncytial virus fusion (RSV-F) protein, comprising, in the 5’ to 3’ direction: a 5’ cap, a 5’ untranslated region (UTR), an open reading frame encoding the RSV-F protein, a 3’UTR, and a 3’ poly-adenine (poly-A) tail; wherein the RSV-F protein comprises an F2 and an F1 domain, wherein the RSV-F protein comprises, relative to SEQ ID NO: 1 or 2, a substitution of a residue for a C residue in both of the F2 and F1 domains, and wherein, when expressed, the RSV-F protein is in the pre-fusion conformation and comprises a disulphide bond formed by the C residues in the F2 and F1 domains. 2. The RNA of claim 1, wherein the F2 domain is the region of the RSV-F protein corresponding to positions 26-109 of SEQ ID NO: 1 or 2, and wherein the F1 domain is the region of the RSV-F protein corresponding to positions 137-523 of SEQ ID NO: 1 or 2. 3. The RNA of claim 1 or 2, wherein the C residue in the F1 domain is within the region of the RSV- F protein corresponding to positions 143-153, 146-150 or 147-149 of SEQ ID NO: 1 or 2; optionally wherein the C residue is at position 148 of the RSV-F protein. 4. The RNA of any preceding claim, wherein the C residue in the F2 domain is within the region of the RSV-F protein corresponding to positions 99-105, 100-104 or 102-104 of SEQ ID NO: 1 or 2; optionally wherein the C residue is at position 103 of the RSV-F protein. 5. The RNA of any preceding claim, wherein the RSV-F protein comprises, relative to SEQ ID NO: 1 or 2, the substitution of a D or E residue for S, T, N, H, P, F, L or Q within the region of the RSV-F protein corresponding to positions 474-523 of SEQ ID NO: 1 or 2; optionally D486S/H/N/T/P or E487Q/T/S/L/H; optionally D486S/T/N/P; optionally D486S. 6. The RNA of any preceding claim, wherein the RSV-F protein further comprises, relative to SEQ ID NO: 1 or 2, the substitution of an S residue at position 190, 55, 62, 155, or 290 of the RSV-F protein for I, Y, L, H, or M; optionally said substitutions at position 190; optionally S190I. 7. The RNA of any preceding claim, wherein the RSV-F protein comprises, relative to SEQ ID NO: 1 or 2, the substitutions T103C, I148C, S190I and D486S 8. A recombinant RNA encoding an RSV-F protein, comprising, in the 5’ to 3’ direction: a 5’ cap, a 5’ UTR, an open reading frame encoding the RSV-F protein, a 3’UTR, and a 3’ poly-A tail; wherein the RSV-F protein comprises: a C residue at position 103, a C residue at position 148, Docket No: 70330WO01 an I residue at position 190, and an S residue at position 486; wherein, when expressed, the RSV-F protein is in the pre-fusion conformation and comprises a disulphide bond formed by the C residues. 9. The RNA of any preceding claim, wherein the RSV-F protein comprises an amino acid sequence having at least 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to SEQ ID NO: 1; optionally wherein the RSV-F protein is of the A subtype. 10. The RNA of any of claims 1-8, wherein the RSV-F protein comprises an amino acid sequence having at least 80%, 81% 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to SEQ ID NO: 2; optionally wherein the RSV-F protein is of the B subtype. 11. The RNA of any preceding claim, wherein the RNA is for immunisation of a subject. 12. The RNA of any of preceding claim, wherein the RNA is non-self-replicating RNA. 13. The RNA of any of preceding claim, comprising a modified ribonucleotide, optionally wherein the modified ribonucleotide is 1mΨ. 14. The RNA of claim 13, wherein the RNA comprises 1mΨ and neither standard U ribonucleotides nor other modified U ribonucleotides; optionally wherein the RNA comprises 1mΨ and neither standard U ribonucleotides nor other modified ribonucleotides. 15. The RNA of any preceding claim, wherein the 5’ UTR comprises (i) an RNA sequence according to SEQ ID NO: 18 or (ii) an RNA sequence at least 70%, 80%, 85%, 90%, 95% or 97% identical to SEQ ID NO: 18; and/or, optionally and, wherein 3’ UTR comprises (i) an RNA sequence according to SEQ ID NO: 19 or (ii) an RNA sequence at least 70%, 80%, 85%, 90%, 95%, 97% or 98% identical to SEQ ID NO: 19. 16. The RNA of any of claims 1-14, wherein the 5’ UTR comprises (i) an RNA sequence according to SEQ ID NO: 20 or (ii) an RNA sequence at least 70%, 80%, 85%, 90%, 95%, 97% or 98% identical to SEQ ID NO: 20; and/or, optionally and, wherein 3’ UTR comprises (i) an RNA sequence according to SEQ ID NO: 21 or (ii) an RNA sequence at least 70%, 75%, 80%, 85%, 90% 95%, 96%, 97%, 98%, 99% or 99.5% identical to SEQ ID NO: 21. Docket No: 70330WO01 17. The RNA of any of claims 1-15, wherein the RNA comprises (i) SEQ ID NO: 4; or (ii) an RNA sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or 99.9% identical to SEQ ID NO: 4. 18. The RNA of any preceding claim, wherein the 3’ poly-A tail comprises a contiguous stretch of 100-500 A ribonucleotides; or wherein the 3’ poly-A tail comprises at least two non-contiguous stretches of A ribonucleotides 25-35 and 65-90 ribonucleotides in length orientated in the 5’ to 3’ direction respectively. 19. The RNA of any preceding claim, wherein the RNA is able to elicit a pre-fusion RSV-F-specific antibody response in vivo; optionally wherein the antibody response is an IgG response. 20. The RNA of any preceding claim, wherein the RNA is able to elicit a neutralising antibody response against RSV in vivo; optionally wherein the RSV is of the A subtype. 21. The RNA of any preceding claim, wherein the RNA is able to elicit a cross-neutralising antibody response against strains of both RSV-A and RSV-B subtypes in vivo. 22. A lipid nanoparticle comprising the RNA of any of preceding claim. 23. A pharmaceutical composition comprising the RNA of any of claims 1-21 or lipid nanoparticle of claim 22; optionally for use in medicine. 24. The pharmaceutical composition for use of claim 23, for use in a method of vaccinating a subject against RSV; optionally wherein the subject is: a human infant, optionally 2-6 months old; a human older adult, optionally ≥60 years old; or a pregnant human female, optionally ≥28 weeks pregnant. 25. A method of inducing an immune response against RSV in a subject, comprising administering to the subject an immunologically effective amount of the RNA of any of claims 1-21, lipid nanoparticle of claim 22, or pharmaceutical composition of claim 23.