1. A liposome in which an immunogen-coding RNA is encapsulated, wherein the liposome contains a cationic lipid and the ratio of N: P of the liposome to RNA is from 1: 1 to 20: 1.2. The liposome according to claim 1, the diameter of which is in the range from 50 to 220 nm. The liposome according to claim 1, in which the RNA is a self-replicating RNA. The liposome of claim 3, wherein the self-replicating RNA encodes (i) an RNA-dependent RNA polymease that can transcribe RNA from a self-replicating RNA molecule and (ii) an immunogen. The liposome according to claim 4, in which the self-replicating RNA has two open reading frames, the first of which encodes an alpha virus replicase, and the second encodes an immunogen. The liposome according to claim 2, where the RNA is a self-replicating RNA. The liposome of claim 6, wherein the self-replicating RNA encodes (i) an RNA-dependent RNA polymease that can transcribe RNA from a self-replicating RNA molecule and (ii) an immunogen. The liposome of claim 7, wherein the self-replicating RNA has two open reading frames, the first of which encodes an alpha virus replicase, and the second encodes an immunogen. A liposome according to any one of claims 1 to 8, in which the length of the RNA is from 9000 to 12000 nucleotides. A liposome according to any one of claims 1 to 8, wherein the immunogen can induce an in vivo immune response against a bacterium, virus, fungus or parasite. The liposome of claim 10, wherein the immunogen can induce an in vivo immune response against the respiratory syncytial virus glycoprotein F. The liposome according to any one of claims 1 to 8, where the ratio of N: P liposomes and RNA is from 2: 1 to 18: 1.13. The liposome according to any one of claims 1 to 8, where the ratio of N: P liposomes and RNA is from 3: 1 to 11: 1.14. Liposome according to any one of claims 1 to 8, where the ratio of N: P liposome1. Липосома, в которую инкапсулирована иммуноген-кодирующая РНК, где липосома содержит катионный липи
