Press releases

San Francisco AIDS Foundation highlights significant decline in STIs due to Doxy PEP

Findings were presented during this year’s Conference on Retroviruses and Opportunistic Infections

Bella Mungioli, 

SAN FRANCISCO, March 4, 2024 – Hyman Scott, Medical Director, San Francisco AIDS Foundation, attended CROI 2024 (Conference on Retroviruses and Opportunistic Infections) March 3-6, and presented: “Doxycycline PEP (Doxy PEP): High uptake and Significant Decline in STIs after Clinical Implementation.” The study team evaluated the impact of Doxy PEP on STIs at Magnet and found that among those who started Doxy PEP,  bacterial sexually transmitted infections (STIs) decreased by nearly 60% in less than a year. The decline was highest for syphilis (78%) and Chlamydia (67%), although there was no significant impact on Gonorrhea (11%) in this early analysis.

In late 2022, San Francisco AIDS Foundation was one of the first organizations in the U.S. to roll out a new intervention for the prevention of sexually transmitted infections: “Doxy PEP” after a randomized controlled study with cisgendermen who have sex with men and transgender women showed that one dose of the antibiotic doxycycline within 24-72 hours after sex significantly reduced rates of chlamydia, gonorrhea, and syphilis by nearly 70%. Since this service began at our sexual health clinic Magnet, we’ve provided Doxy PEP to more than 2,300 clients. 

“We are noticing an impact of Doxy PEP on reducing sexually transmitted infections,” said Jorge Roman, MSN, FNP-BC, AAHIVS, Senior Director of Clinical Services. “For so long, we have only been able to rely on condoms for STI prevention–and we know that condoms don’t work for everyone. There is a clear need for additional strategies to reduce STI rates–in San Francisco, and across the U.S., the number of cases of chlamydia, syphilis, and gonorrhea have been on the rise for many years. It is exciting to have a new tool that we can make available for STI prevention.” 

Doxy PEP was offered to all active PrEP clients at their clinical visits starting in November 2022. Of the 3,081 active PrEP clients, 39% received Doxy PEP during the study period. Among those who received Doxy PEP, STI incidence declined from 18.1% in the first quarter of the study period to 7.5% in the last quarter. Among non‐Doxy PEP users, STI rates remained stable with no significant drop.

The majority of clients who received Doxy PEP were gay, cisgender men, and over 50% identified as BIPOC. 

Doxy PEP uptake was high reflecting strong demand when offered as part of routine PrEP care. Overall STI incidence declined rapidly after implementation demonstrating the high impact of this intervention in a real‐ world setting. Continued evaluation of uptake, adherence, and impact on bacterial STIs will be essential as Doxy PEP implementation expands.  

“The evidence now overwhelmingly supports the use of DoxyPEP for STI prevention and we see benefits of an aggressive rollout to the populations who are most likely to benefit,” remarked Hyman Scott, MD, MPH, Medical Director, San Francisco AIDS Foundations. “Despite reservations about widespread adoption, including concerns about antimicrobial resistance, the proactive distribution of DoxyPEP stands poised as a powerful tool to prevent STIs across our communities.”

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About the author

San Francisco AIDS Foundation

San Francisco AIDS Foundation promotes health, wellness and social justice for communities most impacted by HIV through sexual health and substance use services, advocacy, and community partnerships. Each year more than 21,000 people rely on SFAF programs and services, and millions more access SFAF health information online.