California Detects First U.S. Non-Travel Clade I Mpox

Health officials have identified three Clade I mpox cases in California, including the first U.S. infections without recent international travel identified in Long Beach and Los Angeles County, raising concern about possible local transmission. The patients were hospitalized and are now reported to be recovering at home; investigators have not yet found clear links tying the cases together. Los Angeles County, Long Beach, the California Department of Public Health and the U.S. Centers for Disease Control and Prevention are conducting contact tracing, reviewing exposures and working to identify transmission routes. Clade I, which has circulated widely in central and eastern Africa and is considered more virulent than the Clade II strain behind the 2022 U.S. outbreak, has been associated with large numbers of infections and deaths there. Officials say overall public risk remains low but urge vigilance, testing, early detection and vaccination (the two-dose JYNNEOS vaccine) for people at higher risk while surveillance and investigations continue.