The present invention provides mRNAs usable as vaccines against lassa virus (LASV) infections. Further, the invention relates to (pharmaceutical) compositions and vaccines comprising said mRNAs and their use for treatment or prophylaxis of a lassa virus infection. The present invention further features a kit comprising the mRNAs, (pharmaceutical) compositions or vaccines and a method for treatment or prophylaxis of lassa virus infections using said mRNAs, pharmaceutical) compositions or vaccines.
