SF health department reports September mpox spike

  • by John Ferrannini, Assistant Editor
  • Friday October 13, 2023
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San Francisco Department of Public Health staff had an mpox vaccination booth at the Folsom Street Fair September 24. Photo: Rick Gerharter
San Francisco Department of Public Health staff had an mpox vaccination booth at the Folsom Street Fair September 24. Photo: Rick Gerharter

San Francisco saw an uptick in mpox cases last month, according to the city's Department of Public Health.

As the Bay Area Reporter previously reported, DPH had warned August 30 that there'd been seven cases in the prior five weeks. Through June the city had been averaging one case per month since January, health officials noted at that time.

On October 13, DPH reported that there were 19 cases in September. According to the health department's tracker, most of those occurred before the Folsom Street Fair September 24. Health officials had an mpox vaccination booth at the leather and kink festival in the city's South of Market neighborhood.

There has been one case reported so far in October, according to the case count tracker.

"While mpox cases remain low compared to 2022, this is an increase from an average of one case per month from January to June 2023," DPH noted in its San Francisco Monthly STI Report released October 13.

Dr. Stephanie Cohen, a straight ally who is the section director for HIV/STI prevention with the health department, told the Bay Area Reporter that it is unclear why the increase in cases is coming now.

"We know mpox is circulating in sexual networks and its primarily spread during intimate contact during oral and anal sex. That's how cases are spread," she said. "While we don't know exactly why cases are increasing now, it's important to point out our cases are much lower than in 2022 because of the robust vaccine rollout that occurred during the 2022 outbreak and the fantastic work of community members, organizations, and health systems providing vaccine to our communities."

Cohen also said that 40% of those who received the first dose of mpox vaccine didn't return for a second.

"It's never too late," she added.

With its most recent update on case counts of sexually transmitted infections in the city, DPH is using the opportunity to tout people getting vaccinated for mpox. According to health officials, two doses of the Jynneos vaccine, given about a month apart, provide the best protection against the disease that has largely been infecting gay and bisexual men.

Over 50,000 doses of the mpox vaccine were distributed last year in San Francisco, DPH stated, covering 42% of all people living with HIV in the city and 65% of people who had received PrEP at San Francisco City Clinic prior to June 2022.

"The Jynneos vaccine is safe and effective, and completion of the two-dose series provides improved protection compared to one dose," DPH highlighted in its most recent STI monthly report. "No vaccine is 100% effective and people who have been vaccinated may still get mpox, but vaccination may decrease illness severity and reduce the risk of hospitalization."

While anyone who wants protection from mpox infection may seek a vaccine, DPH strongly recommends and encourages two-dose vaccination for all people living with HIV, anyone taking or eligible to take HIV PrEP, and all men, trans people, and nonbinary people who have sex with men, trans people, or nonbinary people. These groups are likely to be among those most affected if mpox cases were to increase again in San Francisco, the department noted in its August advisory.

The October advisory reiterated six recommendations for clinicians: maintaining awareness of what lesions look like, strongly recommending and administering the vaccine, and counseling patients on risk reduction by using condoms and reducing one's total number of different sexual partners.

Other recommendations include talking about mpox risk assessment and vaccination status in all sexual health visits for men, trans, and nonbinary people; and providing mpox vaccine as part of a comprehensive package that includes discussion of PrEP, and other HIV and sexually transmitted infection-related issues. Local health officials are also asking those who've contracted the mpox virus to take part in the STOMP Trial, which is "a national randomized controlled trial on the efficacy and safety of tecovirimat (TPOXX)."


According to the latest monthly report, which covers data through the end of August, STIs are still under 2022 numbers. Public health experts told the B.A.R. in June that the plunge in diagnoses of bacterial STIs could be due to behavior change after last summer's mpox outbreak.

According to the most recent numbers, diagnoses of gonorrhea in San Francisco from January 1 to August 31 totaled 3,296, compared with 3,580 cases over those dates the previous year. For cases of male rectal gonorrhea that number was 1,116, compared with 1,390 in 2022.

Diagnoses of chlamydia in 2023 through August 31 totaled 3,946, compared with 4,347 in 2022. Diagnoses of syphilis in 2023 through August 31 totaled 895, compared with 1,204 in 2022.

DPH and the San Francisco AIDS Foundation did not return requests for comment for this report as of press time.

For information on the mpox vaccine, go to sf.gov/information/mpox-vaccine.

Updated, 10/18/23: This article has been updated with comments from Dr. Stephanie cohen of the health department.

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