Lassa Fever Vaccine Advances in West Africa

West African Ministers of Health today pledged their joint commitment to advance the development of, and readiness for, much-needed vaccines against Lassa fever.

First identified in 1969 in Nigeria, Lassa fever has a devastating impact on local populations.

Currently, there are no licensed vaccines to protect against Lassa fever.

As of September 8, 2025, these Ministers of Health are supported by the Coalition for Epidemic Preparedness Innovations (CEPI) and the International AIDS Vaccine Initiative (IAVI).

IAVI has developed the most advanced Lassa fever vaccine candidate, funded by CEPI and the European & Developing Countries Clinical Trials Partnership.

IAVI's promising vaccine candidate is currently being evaluated in a Phase IIa clinical trial in Ghana, Liberia, and Nigeria, the most advanced study of a Lassa fever vaccine to date.

According to the WHO, Lassa fever, an acute viral illness, is endemic in Benin, Ghana, Guinea, Liberia, Mali, Nigeria, and Sierra Leone, but is likely also present in other West African countries.

The Lassa virus is primarily transmitted to humans via contact with food or household items contaminated with rodent urine or faeces. Person-to-person transmission can also occur, particularly in healthcare settings that lack adequate infection prevention and control measures.

The overall case fatality rate is 1%, but the observed case fatality rate among patients hospitalized with severe Lassa fever is 15% or higher.

As of week #33 in 2025, there were no Lassa fever cases in the USA>