MVA-BN WEV is a vaccine candidate targeting Western, Eastern and Venezuelan equine encephalitis viruses. The vaccine is being developed under a contract with the U.S. Government.
Western, Eastern and Venezuelan equine encephalitis viruses vary in infection rates and severity of disease, although all three pathogens are associated with risks of flu-like symptoms, potential central nervous disorders, and death. The virus is spread by mosquitos to humans and can result in the rare condition of encephalitis in about 5% of the people that become infected. In the United States, an increase in cases of Eastern equine encephalitis, known also as Triple E, has been reported over the past years, and in 2019 almost 40 cases, including 15 deaths were reported by the CDC in what is the largest ever recorded outbreak of Triple E. There are currently no approved vaccines against any of the equine encephalitis viruses.