The San Francisco Department of Public Health (SFDPH) is currently monitoring a new strain of mpox, known as clade I, following a case reported in San Mateo County. This marks the first known instance of clade I mpox in the United States. SFDPH is collaborating with Bay Area, state, and federal partners to keep track of this development. There are no reported cases of clade I mpox in San Francisco at present, and the risk to the public remains low.
In August 2024, the World Health Organization declared the outbreak of clade I mpox in central and east Africa a public health emergency of international concern. The outbreak has been more extensive than previous occurrences in the Democratic Republic of Congo (DRC), spreading to neighboring countries such as Burundi, Central African Republic, Republic of the Congo, Rwanda, and Uganda. Additionally, travel-related cases have been identified in Germany, India, Kenya, Sweden, and Thailand.
Mpox is categorized into two types: clade I and clade II. Each type is further divided into subclades 1a and 1b for clade I and IIa and IIb for clade II. In 2024 so far, there have been 31 confirmed cases of clade II mpox in San Francisco.
The SFDPH emphasizes that “the two-dose mpox vaccine provides the best protection against mpox,” recommending vaccination based on CDC eligibility criteria. Information about recommendations can be found on their website at sf.gov/mpox.
Individuals eligible for vaccination can receive their second dose if it has been at least 28 days since their first dose without needing to restart the series if delayed beyond 28 days. Booster doses are not currently advised for those who have completed the two-dose series or for individuals previously infected with mpox.
Vaccines are available through health systems and clinics. Uninsured individuals or those facing difficulties accessing care can visit SFDPH’s San Francisco City Clinic.
SFDPH assures continued updates to the community regarding any necessary actions to safeguard public health. More information is available on their website sf.gov/mpox.
