The invention relates to mRNA comprising lipid nanoparticles and their medical uses. The lipid nanoparticles of the present invention comprise a cationic lipid according to formula (I), (II) or (III) and/or a PEG lipid according to formula (IV), as well as an mRNA compound comprising an mRNA sequence encoding an antigenic peptide or protein. The invention further relates to the use of said lipid nanoparticles as vaccines or medicaments, in particular with respect to influenza or rabies vaccination.