Four years after the outbreak that put mpox on front pages worldwide, federal disease detectives have reached a conclusion that changes how the virus should be understood in the United States. It is not returning. It never left, and the pattern now looks more permanent.
A CDC report published Thursday in Morbidity and Mortality Weekly Report analyzed 5,322 mpox cases reported nationally during 2024 and 2025. Its central finding is stated plainly: persistent transmission of clade IIb monkeypox virus, with wide geographic spread over the last three years, "suggests a transition toward endemic circulation."
