Researchers from San Francisco and Seattle have found that Doxy PEP is an effective strategy in reducing sexually transmitted infections (STIs) like gonorrhea, chlamydia, or syphilis. Doxycycline is an antibiotic traditionally used for other bacterial infections like acne and malaria, but when used as a post-exposure prophylactic within three days after unprotected sex, it reduces infections by more than 60%. 

Can you take doxycycline to prevent STDs?

A clinical study conducted with the San Francisco Department of Health (SFDPH), Zuckerberg San Francisco General, University of California, San Francisco, and the University of Washington ended early when they found Doxy PEP to be effective among 554 men who have sex with men and transgender women living with HIV or taking an HIV pre-exposure prophylaxis (PrEP). 

“PrEP transformed HIV prevention, and I think that Doxy PEP is going to transform STI prevention in a similar way,” says Hyman Scott, MD, MPH, Medical Director of San Francisco AIDS Foundation. 

Until now, STI prevention strategies have been mostly behavioral, like wearing a condom or engaging in non-penetrative sex. Infection rates for STIs, mainly syphilis, gonorrhea, and chlamydia, have been rising for the last decade and increased even further during the COVID-19 epidemic. Syphilis cases increased by 26% from 2020 to 2021, the highest number since 1991. Gonorrhea and chlamydia are also on the rise. While these bacterial STIs can be spread through childbirth and breastfeeding, unprotected sex is one of the main paths to infection–and it’s on the rise. 

While PrEP protects up to 99% against HIV, it doesn’t prevent other STIs. Further, HIV PrEP roll-out has been slow due to cost and access issues, but doxycycline won’t have the same problem. It’s an inexpensive medication that healthcare providers have been prescribing for years to treat acne and malaria. Now, it’s going to have a new purpose: slowing down the global rate of sexually transmitted infections. 

Some cases of syphilis lead to hearing loss. Trachoma is a disease caused by the chlamydia bacteria and causes more vision loss and blindness than any other infection in the world. In under-resourced areas like sub-Saharan Africa, lack of access to proper health screenings and medication can perpetuate infections among those living in poverty and without proper public health resources. 

“In retrospect, we’ve slow-walked PrEP rollout across the country, and we shouldn’t slow-walk Doxy PEP rollout. We’re still trying to play catch up with increasing access and addressing inequities in PrEP uptake. We have the opportunity to do things differently with Doxy PEP,” says Scott. 

The Doxy PEP clinical trial findings were shared this summer at the International AIDS Conference to an audience of expecting medical and health professionals. 554 participants randomized to doxycycline PEP (Doxy PEP) had a 66% (HIV-negative and on PrEP) and 62% (PLWH) reduction in STIs compared to those randomized to standard care and no Doxy PEP. The STIs that were studied include syphilis, gonorrhea, and chlamydia. 

How often do I take doxycycline for STIs?

In October, the San Francisco Department of Health followed up their study by publishing recommendations and guidelines on how to offer Doxy PEP for those at risk of contracting STIs. However, recommended protocol at the federal level has not happened yet. Providers in other cities across America are hesitant to offer doxycycline without from the CDC, who has released considerations but not yet a guideline. According to San Francisco’s guidelines, “200 mg of doxycycline should be taken ideally within 24 hours but no later than 72 hours after condomless oral, anal or vaginal sex.” Doxycycline is safe enough to take daily, depending on the frequency of unprotected sex, but no more than 200 mg should be taken within 24 hours. 

Where can I get Doxy PEP?

Magnet, San Francisco AIDS Foundation’s sexual health clinic, is actively providing Doxy PEP as a safe and effective tool to prevent STIs to Magnet clients. It’s also available at San Francisco City Clinic. Even if your local clinic or provider isn’t offering it, it’s important for those at risk for contracting STIs to ask their doctors or clinicians. 

“We want people to be empowered. Not everyone can wait in line for five hours to get a vaccine, but that doesn’t mean they’re at any less risk of acquiring an STI,” Scott adds concerning the equity is who has access to sexual health programs.