The first case in the U.S. of a more severe strain of mpox was reported in San Mateo County, the California Department of Public Health said.

The United States’ first known case of a more severe strain of mpox was confirmed in California, the US Centers for Disease Control and Prevention said Saturday. The risk of clade I mpox to the public remains low,

The unidentified patient had recently returned from Africa, where the virus has caused a deadly epidemic, health officials said.