Susceptibility to monkeypox virus infection: seroprevalence of orthopoxvirus in 4 population samples; France, Bolivia, Laos and Mali

Europe is experiencing an epidemic of monkeypox virus against a background of limited knowledge of population immunity to orthopoxviruses. We tested antibodies neutralizing vaccinia virus in blood samples from Bolivia (n=601), Laos (n=657), Mali (n=255) and France (n=4876). We also tested neutralization of cowpox virus in 4448 French samples, which confirmed extensive cross-immunity between both viruses. Using a cut-off titer of 20, seroprevalence is e.g. monkeypox) infections.Article summary lineSeroprevalence of orthopoxvirus tested on 4 continents is very low, even for people born before the eradication of smallpox, making populations vulnerable to the emergence of zoonotic orthopoxviruses such as monkeypox virus.