San Francisco Faces New Clade I Mpox Cases Amid Ongoing Vaccination Efforts

San Francisco has reported its first confirmed case of clade I mpox, a variant of the virus associated with more severe illness compared to the strain responsible for the 2022 outbreak. The patient, an unvaccinated adult, was hospitalized after close contact with an individual who had recently traveled abroad. Health officials indicate that the patient is recovering, and the overall public risk remains low. However, they are urging individuals at higher risk to complete the two-dose mpox vaccine series in anticipation of summer events.

Unvaccinated SF Patient Hospitalized in City's First Potent Mpox CaseKQED

Since the initial outbreak in 2022, San Francisco has recorded over 1,000 cases of clade II mpox, with the average number of new cases now dropping to under two per week. Wastewater data indicates that clade II is still occasionally detected in the Bay Area. The Centers for Disease Control and Prevention (CDC) has noted that clade I cases have emerged in Western Europe among individuals without documented international travel, suggesting a shift in transmission dynamics.

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The CDC recommends the Jynneos vaccine, a two-dose series, for gay and bisexual men, transgender individuals, and others at high risk, including those with multiple sexual partners or recent sexually transmitted infections. In 2024, the CDC expanded its recommendations to include travelers to countries experiencing clade I outbreaks. The vaccine is available for free, and individuals can receive it through health care providers, community clinics, or pharmacies. Those without insurance can still access the vaccine at designated clinics.

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Dr. Susan Philip, a health officer with the San Francisco Department of Public Health (SFDPH), emphasized that being fully vaccinated is the most effective way to protect against severe illness from mpox. The SFDPH advises anyone experiencing new rashes, blisters, or flu-like symptoms to seek medical advice and inform recent partners for evaluation. Antiviral medications are also available for more severe cases, and early testing can improve health outcomes.

Unvaccinated SF Patient Hospitalized in City's First Potent Mpox Case

Despite the ongoing vaccination efforts, some community members express concern over the accessibility of the vaccine and the potential for misinformation regarding mpox symptoms and transmission. Public health officials are working to address these concerns by providing clear guidance and resources for testing and vaccination.

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While the CDC describes the overall risk of mpox to most Americans as low, it acknowledges that the risk for men who have sex with men is categorized as low to moderate. This discrepancy in risk assessment highlights the need for continued monitoring and public health outreach to ensure that at-risk populations are adequately informed and protected.

Unvaccinated SF Patient Hospitalized in City's First Potent Mpox Case

The SFDPH is actively investigating potential contacts related to the recent clade I case and will provide updates as necessary. Public health officials continue to monitor the situation closely, conducting contact tracing and sequencing samples to better understand transmission patterns and prevent further outbreaks.

Unvaccinated SF Patient Hospitalized in City's First Potent Mpox Case

“Susan Philip underscored that being fully vaccinated remains the strongest protection against serious illness.” — Dr. Susan Philip, Health Officer, SFDPH

Unvaccinated SF Patient Hospitalized in City's First Potent Mpox Case

“provides the best protection against the mpox virus and protects against both clade I and clade II,” — SFDPH Statement

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“Residents who have questions about symptoms, testing, or vaccination can check with local clinics and review the city’s mpox web pages for current guidance and clinic schedules.” — SFDPH Guidance

Unvaccinated SF Patient Hospitalized in City's First Potent Mpox Case