A bivalent Lassa virus mRNA vaccine protects guinea pigs from lethal infection with Lassa virus

The bivalent Lassa virus mRNA-LNP vaccine (LASgpc-mRNA-LNP plus LASnp-mRNA-LNP) fully protected guinea pigs against lethal authentic Lassa virus challenge.

• Why it matters: Lassa fever remains a major public health concern in West Africa, and no licensed vaccine is available, creating an urgent need for effective preventive measures.
• What they did: In a lethal CBA/N mouse model using ML29 and a live-attenuated LASV candidate encoding GPC and NP, monovalent LASgpc-mRNA-LNP and LASnp-mRNA-LNP each protected without detectable neutralizing antibodies; vaccination induced robust LASV GPC- and NP-specific CD4 and CD8 T-cell responses.
• The result: The bivalent formulation provided complete protection in mice at doses where monovalent vaccines failed to protect all mice, and it fully protected guinea pigs against lethal authentic LASV challenge.