San Francisco Confirms First Clade I Mpox Case

City resident hospitalized as health officials urge vaccination for at-risk groups

Apr. 17, 2026 at 9:20pm by

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The San Francisco Department of Public Health has confirmed the city's first case of clade I mpox in an unvaccinated adult who has been hospitalized and is recovering. Health officials are closely monitoring the situation and encouraging anyone at risk of contracting the virus to get vaccinated, as clade II mpox cases continue to occur in San Francisco and throughout California.

Why it matters

The detection of a clade I mpox case in San Francisco is significant, as the 2022 mpox outbreak in the U.S. was primarily driven by the clade II strain. This development underscores the importance of vaccination, especially with summer travel and events approaching, to protect vulnerable populations and prevent the further spread of both clade I and clade II mpox.

The details

The individual with the clade I mpox case reported close contact with someone who had traveled internationally. The San Francisco Department of Public Health stated the current exposure risk is low for those not in higher-risk groups. The mpox vaccine, which protects against both clade I and clade II strains, is available through healthcare providers and local pharmacies. Uninsured residents or those with difficulty accessing care can visit locations listed on the city's website.

  • On April 17, 2026, the San Francisco Department of Public Health confirmed the first clade I mpox case in a city resident.

The players

San Francisco Department of Public Health

The local public health agency responsible for monitoring and responding to infectious disease outbreaks in San Francisco.

Dr. Susan Philip

The San Francisco Health Officer who issued a statement on the clade I mpox case.

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What they’re saying

“SFDPH is closely monitoring mpox. While clade I mpox cases remain rare in the United States, clade II mpox cases continue to occur in San Francisco and throughout California. This development reminds us just how important it is to be fully vaccinated against mpox if you are at risk.”

— Dr. Susan Philip, San Francisco Health Officer

What’s next

The San Francisco Department of Public Health will continue to closely monitor the situation and provide updates to the public. Health officials are urging at-risk individuals to get vaccinated against both clade I and clade II mpox strains.

The takeaway

The detection of a clade I mpox case in San Francisco underscores the need for continued vigilance and vaccination efforts, especially as the city prepares for increased summer travel and events. This development serves as a reminder that mpox remains a public health concern, and proactive measures are crucial to protect vulnerable populations and prevent the further spread of this virus.