Immunisation with lipid formulations with RNA encoding immunogens

A method of eliciting an antibody response against an immunogen in a subject, the method comprising administering intramuscularly to the subject an effective amount of a unit dose of a pharmaceutical composition to elicit the antibody response;

• the pharmaceutical composition comprising ribonucleic acid (RNA) molecules and lipid particles;
• the RNA molecules comprising a sequence that encodes the immunogen;
• the immunogen comprising a respiratory syncytial virus surface fusion glycoprotein, an Epstein-Barr virus immunogen, a cytomegalovirus immunogen, a coronavirus spike polypeptide immunogen, an influenza virus A immunogen, a Varicella zoster virus immunogen, or a flavivirus immunogen;
• the lipid particles comprising:
• (a) from 40 mole % to 60 mole % cationic lipid comprising a tertiary amine, (b) a polyethylene glycol-conjugated (PEG-conjugated) lipid, and (c) from 35 mole % to 50 mole % cholesterol;
• at least 80% of the lipid particles having a diameter from 20 nm to 220 nm;
• the lipid particles encapsulating at least half of the RNA molecules;
• the administering comprising contacting the pharmaceutical composition with skeletal muscle;
• and the subject being a human or a cow.