Doxycycline postexposure prophylaxis for sexually transmitted infections: A systematic review and meta-analysis with trial sequential analysis.

In 30 seconds

This systematic review and meta-analysis assessed doxycycline postexposure prophylaxis (DoxyPEP) versus standard care for bacterial sexually transmitted infections in men who have sex with men and transgender women at high STI risk. Three randomized controlled trials involving 1278 participants were included. DoxyPEP reduced the overall risk of any bacterial STI (pooled RR 0.41, 95% TSA-adjusted CI 0.20-0.85), with larger reductions for chlamydia and syphilis and a smaller reduction for gonorrhea. Trial sequential analysis supported pathogen-specific effects, but uncertainty remained around the composite estimate and long-term antimicrobial resistance.

Key findings

• DoxyPEP reduced any bacterial STI overall (pooled RR 0.41, 95% TSA-adjusted CI 0.20-0.85).
• Chlamydia was reduced (RR 0.22, 95% TSA-adjusted CI 0.12-0.39), as was syphilis (RR 0.24, 95% TSA-adjusted CI 0.13-0.44).
• Gonorrhea showed a smaller reduction (RR 0.79, 95% TSA-adjusted CI 0.66-0.95).
• The composite crossed the TSA monitoring boundary but did not reach its heterogeneity-adjusted required information size; heterogeneity was substantial (I² = 89.1%).

Why it matters

The findings suggest DoxyPEP can reduce several bacterial STIs in the high-risk populations studied, with the strongest effects for chlamydia and syphilis. The smaller gonorrhea benefit and unresolved long-term antimicrobial resistance are important when interpreting the overall prevention signal. Trial sequential analysis strengthens confidence in pathogen-specific effects, while the composite result remains less certain.

What to keep in mind

Only three RCTs were included. The composite estimate had substantial heterogeneity (I² = 89.1%) and did not reach its heterogeneity-adjusted required information size; long-term antimicrobial resistance remained uncertain.