Official announcements from California Department of Public Health or CDC

First U.S. Clade I Mpox Case Confirmed in California's Bay Area

Nov 16, 2024, 08:10 PM

California health officials have confirmed the first known U.S. case of clade I mpox, a more severe strain of the monkeypox virus (MPXV), in San Mateo County, part of the Bay Area. The California Department of Public Health announced on November 16, 2024, that the patient had recently traveled from Eastern Africa and is related to the ongoing outbreak of clade I mpox in Central and Eastern Africa. Clade I mpox was first seen in the Democratic Republic of Congo and is believed to be more severe than clade II, which caused the global outbreak in 2022. The patient was treated in Northern California upon return, and their symptoms are improving. The Centers for Disease Control and Prevention is awaiting the specimen for confirmation testing and is assisting state and local partners to understand more about the case. Officials stated that there is no evidence of local transmission, suggesting the risk to the public remains low.