There has been an increase in travel-related introductions of clade I mpox into California and the U.S. in 2026, and clade II mpox cases have increased in California. Increases in clade I community transmission in Western Europe suggest that additional travel-related clade I mpox cases should be expected in California. Clinicians should have a heightened index of suspicion for mpox and particularly for clade I mpox in individuals who report recent international travel or sexual or intimate contact with someone who recently traveled internationally, especially to an area where clade I is circulating. Providers and assistants including cleaning staff should wear full PPE (gloves, gown, goggles, and fit tested N-95 respirator). Mpox testing should be considered for patients with compatible signs and symptoms (PDF), regardless of vaccination status or previous infection. Providers should report suspect or confirmed clade I mpox cases immediately to their local health department and/or CDPH. Mpox vaccination with two doses is recommended for individuals who may be at risk for mpox including immune compromised individuals and is expected to protect against both clade I and clade II mpox or any subclades.
Full Advisory: Increase in Introductions of Clade I Mpox and Increases in Clade II Mpox Within California
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