Doxycycline after sex to prevent STIs and track antibiotic resistance across U.S. cities
The Doxy-PEP Impact Study: a multi-city US longitudinal cohort to evaluate doxy-PEP field effectiveness, investigate associated antimicrobial resistance, and establish doxy-PEP to need ratios
This project follows people at higher risk who take doxycycline after condomless sex to see if it lowers sexually transmitted infections and how it affects antibiotic resistance.
Quick facts
| Grant type | R01 grant |
|---|---|
| Study type | NIH-funded research |
| Funding institution | University of California, San Francisco NIH-funded |
| Lab location | 1 site (San Francisco, United States) |
| Project ID | NIH-11360089 on NIH RePORTER |
What this research studies
If you join, researchers will follow people at elevated risk for recurrent STIs over time across multiple U.S. cities to see how doxycycline taken after condomless sex is used in real life. Participants will be asked about when they take the medication, how often they continue it, and will receive regular STI testing and clinical follow-up. The study will also collect bacterial specimens to look for signs of antibiotic resistance that might arise with broader doxycycline use. Teams aim to compare who uses doxy-PEP, how well people stick with it, and how much medication is needed for the populations most likely to benefit.
Who could benefit from this research
Good fit: Ideal candidates are people at elevated risk for recurrent bacterial STIs—especially men who have sex with men, people living with HIV, people taking HIV PrEP, those with recent STIs, and younger adults under 30 who live near participating sites.
Not a fit: People at low risk for STIs, those who cannot take doxycycline (for example, due to allergy or pregnancy), or those unable to attend follow-up at a study site are unlikely to benefit directly from participation.
Why it matters
Potential benefit: If successful, this work could help lower STI rates in high-risk groups and guide safer, more equitable use of doxycycline post-exposure.
How similar studies have performed: Randomized trials have already shown large reductions in chlamydia and syphilis (>80%) and substantial reductions in gonorrhea (>50%) with doxy-PEP, but real-world uptake and long-term resistance effects are less well understood.
Where this research is happening
San Francisco, United States
- University of California, San Francisco — San Francisco, United States (Active)
Researchers
- Principal investigator: Luetkemeyer, Anne Frey — University of California, San Francisco
- Study coordinator: Luetkemeyer, Anne Frey
About this research
- This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
- Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
- For full project details, budget, and progress reports, visit the official NIH RePORTER page below.