California public health authorities are calling on at-risk residents to get vaccinated against mpox as case numbers climb across the state. The California Department of Public Health reported this month that the weekly average of clade II mpox cases in 2026 is more than double the rate seen in previous years, with 14.5 cases per week compared to 5.8 in 2024 and 3.4 in 2025.
San Francisco recorded its first case of clade I mpox earlier in April, making it the seventh identified clade I case in California since November 2024. The individual contracted the disease through contact with someone who had traveled internationally, has been hospitalized, and is recovering. Clade I is the more severe strain, carrying a mortality rate of between 1% and 10%, compared to less than 1% to 4% for clade II, which caused the 2022 global outbreak.
CDPH Director and State Public Health Officer Dr. Erica Pan said the department is closely monitoring mpox activity statewide and emphasized the urgency of vaccination ahead of summer travel and large public events. The two-dose vaccine provides protection against both strains. The department is strongly encouraging at-risk individuals, including gay and bisexual men and anyone planning to travel to regions where clade I has been reported including parts of Europe and Africa, to ensure they are fully vaccinated.
Mpox spreads primarily through close skin-to-skin contact with an infected person. Those exposed may develop flu-like symptoms followed by a painful, blister-forming rash that can appear on the extremities and genital areas and take between two and four weeks to clear. The World Health Organization notes that hundreds or even thousands of sores can develop on the body in severe cases. The risk of serious illness and hospitalization is highest for individuals with weakened immune systems, according to Dr. Rita Nguyen, assistant state public health officer.
Information on receiving the mpox vaccine is available through the California Department of Public Health at cdph.ca.gov.
