Official CDC travel advisories and announcements

First U.S. Case of Severe Clade I Mpox Reported in San Mateo County, California

Nov 16, 2024, 08:54 PM

U.S. health officials have confirmed the first known case of clade I mpox in the United States in San Mateo County, California. The case was identified in a traveler who recently returned from Eastern Africa. Clade I mpox, historically seen in the Democratic Republic of Congo, is considered more severe than the clade II strain that caused the global outbreak starting in 2022. The patient is currently isolated at home with mild symptoms that are improving, and public health authorities state that the risk to the public is low with no evidence of local transmission. The Centers for Disease Control and Prevention (CDC) is conducting further testing to confirm the case and is assisting state and local partners in monitoring the situation.