Emergent BioSolutions Inc. announced that it has dosed the first participant in its Phase 1 study evaluating the safety and immunogenicity of EBS-LASV, a recombinant VSV-vectored Lassa virus vaccine candidate being developed for prevention of disease caused by Lassa virus infection. Emergent and CEPI (the Coalition for Epidemic Preparedness Innovations) are co-funding this program. This Phase 1 study, a randomized, placebo-controlled, dose-escalation study, will evaluate the safety and immunogenicity of Emergent's rVSV-vectored Lassa virus vaccine in approximately 36 healthy adults at the Navrongo Health Research Centre and Kintampo Health Research Centre in Ghana.

View the clinical trial registry. First described in the 1950s, the virus was identified in 1969 after two missionary nurses died from the disease in the Nigerian town of Lassa. The virus is spread to humans via contact with food or household items that have been contaminated with urine or feces from infected Mastomys rats.

Person-to-person transmission occurs in both community and healthcare settings, where the virus can spread via contaminated medical equipment. Sexual transmission of Lassa virus has also been reported. About 80% of people who become infected have no symptoms. One in five infections results in severe disease, where the virus affects several organs such as the liver, spleen and kidneys.

The virus is endemic in Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, and Nigeria, but probably exists in other West African countries as well. There is currently no approved vaccine or therapeutic that protects against or treats Lassa fever. There have been outbreaks of Lassa fever in Liberia, Nigeria, and Sierra Leone.