WHO recommendation on doxycycline PEP (200 mg within 72 hours after sex) to prevent bacterial STIs in MSM and transgender women.
What this guideline saysGMJ summary
This guideline presents WHO’s first recommendation on doxycycline post-exposure prophylaxis (PEP) for preventing bacterial sexually transmitted infections. Based on moderate- to high-certainty evidence from three randomised controlled trials, WHO conditionally recommends that doxycycline PEP may be offered to men who have sex with men and transgender women as part of a comprehensive sexual health package.
Doxycycline PEP involves taking a single 200-mg dose within 72 hours (ideally within 24 hours) after condomless sex. Evidence shows it reduces the incidence of syphilis by 80% (RR 0.20), chlamydia by 85% (RR 0.15), and gonorrhoea by approximately 48% (RR 0.52), although effectiveness against gonorrhoea depends on local tetracycline resistance prevalence. No difference in serious adverse events was observed compared with no prophylaxis.
Given concerns about antimicrobial resistance, WHO strongly encourages context-appropriate antimicrobial resistance monitoring alongside doxycycline PEP implementation. Priority should be given to men who have sex with men and transgender women with recent or recurrent STIs—especially syphilis—and those in high-incidence sexual networks. The intervention should complement, not replace, other prevention strategies including condoms, testing and partner services.
Key pointsfor clinicians
- Doxycycline PEP: 200 mg taken as a single dose within 72 hours (ideally within 24 hours) after condomless sex
- Reduces syphilis incidence by 80% (RR 0.20; 95% CI 0.11–0.37), chlamydia by 85% (RR 0.15; 95% CI 0.10–0.23), and gonorrhoea by 48% (RR 0.52; 95% CI 0.40–0.68)
- Avoid repeat dosing within any 24-hour period due to doxycycline's long half-life
- Prioritise men who have sex with men and transgender women with recent or recurrent STIs, especially syphilis, and those in high-incidence sexual networks
- Provide as part of comprehensive sexual health services including counselling, STI testing and treatment, HIV prevention and linkage to care
- Products containing iron, magnesium or calcium (including supplements and dairy) should be taken at least a few hours apart from doxycycline to avoid reduced absorption
- Context-appropriate antimicrobial resistance monitoring is strongly encouraged alongside policy implementation
- No difference in grade 3 or 4 adverse events compared with no doxycycline PEP (RR 0.84; 95% CI 0.43–1.67)
Doxycycline PEP efficacy against bacterial STIs in men who have sex with men and transgender womenextracted from the guideline
| Infection | Relative risk (95% CI) | Risk reduction | Evidence certainty |
|---|---|---|---|
| Syphilis | 0.20 (0.11–0.37) | 80% | High |
| Chlamydia | 0.15 (0.10–0.23) | 85% | High |
| Gonorrhoea | 0.52 (0.40–0.68) | 48% | Moderate |
| Any STI (chlamydia, gonorrhoea or syphilis) | 0.27 (0.15–0.47) | 73% | Moderate |
ApplicabilityGeorgia and the region
Georgia and the South Caucasus region face challenges in STI prevention and control among key populations, including men who have sex with men and transgender women, who often experience stigma and barriers to accessing sexual health services. Implementation of doxycycline PEP would require national programmes to establish: (1) baseline STI and antimicrobial resistance surveillance capacity, particularly for tetracycline resistance in Neisseria gonorrhoeae; (2) stigma-free, accessible service delivery models through sexual health clinics, primary care or community-based services; (3) integration with existing HIV prevention programmes (including PrEP services where available); (4) clear prescription and dispensing pathways; and (5) community engagement and peer-led education. Cost and pharmacy regulations will be important feasibility considerations. Given the conditional nature of the recommendation and antimicrobial resistance concerns, pilot implementation with robust monitoring would be advisable before national scale-up.
Questions this guideline answers
When exactly should doxycycline be taken after sex?
Ideally within 24 hours, and no later than 72 hours after condomless sex. Do not take more than one 200-mg dose in any 24-hour period, even after multiple sexual exposures, because of doxycycline's long half-life.
Does doxycycline PEP work against all STIs?
No. It is highly effective against syphilis (80% reduction) and chlamydia (85% reduction), and moderately effective against gonorrhoea (48% reduction), although effectiveness against gonorrhoea depends on local tetracycline resistance rates. It does not prevent HIV or viral STIs.
Who should be prioritised for doxycycline PEP?
Men who have sex with men and transgender women with recent or recurrent STIs—especially syphilis—and those in high-incidence sexual networks or settings where STIs are circulating at higher than usual levels. Eligibility should be periodically reassessed based on STI incidence, sexual behaviour, preferences and medication tolerance.
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Other guidelines on this topic
- Issuer
- World Health Organization
- Type
- Guideline
- Edition
- 1st edition, 2026
- Status
- Current
- Published
- 2026-07-14
- Languages
- English
- Scope
- Prevention of bacterial sexually transmitted infections (syphilis, chlamydia, gonorrhoea) using doxycycline post-exposure prophylaxis in men who have sex with men and transgender women
- Audience
- Clinicians, sexual health service providers, public health professionals, policymakers, HIV/STI programme managers
- Pages
- 18
- Licence
- CC BY-NC-SA 3.0 IGO
- ISBN
- 978-92-4-012411-0
- Evidence
- GRADE-rated recommendations based on systematic review of randomised controlled trials and qualitative evidence synthesis
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