A MOPEVAC multivalent vaccine induces sterile protection against New World arenaviruses in non-human primates.

Pathogenic New World arenaviruses (NWAs) cause haemorrhagic fevers and can have high mortality rates, as shown in outbreaks in South America. Neutralizing antibodies (Abs) are critical for protection from NWAs. Having shown that the MOPEVAC vaccine, based on a hyperattenuated arenavirus, induces neutralizing Abs against Lassa fever, we hypothesized that expression of NWA glycoproteins in this platform might protect against NWAs. Cynomolgus monkeys immunized with MOPEVAC, targeting Machupo virus, prevented the lethality of this virus and induced partially NWA cross-reactive neutralizing Abs. We then developed the pentavalent MOPEVAC vaccine, expressing glycoproteins from all pathogenic South American NWAs. Immunization of cynomolgus monkeys with MOPEVAC induced neutralizing Abs against five NWAs, strong innate followed by adaptive immune responses as detected by transcriptomics and provided sterile protection against Machupo virus and the genetically distant Guanarito virus. MOPEVAC may thus be efficient to protect against existing and potentially emerging NWAs.