Post-Sex Doxycycline Slashes STI Risk in HIV PrEP Users

TOPLINE:

Among individuals using HIV pre-exposure prophylaxis (HIV PrEP), doxycycline post-exposure prophylaxis (doxyPEP) is associated with a substantial decline in chlamydia and syphilis incidence.

METHODOLOGY:

• Researchers conducted a retrospective cohort study using data from a large healthcare system in California to assess doxyPEP usage and changes in incidence of bacterial sexually transmitted infections (STIs) before and after its initiation among individuals using HIV PrEP.
• Population receiving doxyPEP were identified by doxyPEP dosing instructions from pharmacy data (ie, 200 mg within 72 hours of sex) and followed up for a median of 5.7 months.
• Among 11,551 HIV PrEP users (mean age, 39.9 years; 95.1% men), 2253 were dispensed doxyPEP (98.9% men) and followed up from their first recorded STI test on or after November 1, 2020, until December 31, 2023, or discontinuation of health plan membership.
• Primary outcomes measured quarterly positivity rates for incident chlamydia, gonorrhea, and syphilis infections.

TAKEAWAY:

• Overall, mean quarterly positivity rates significantly decreased after starting doxyPEP for chlamydia (rate ratio [RR], 0.21; P P P = .048).
• Individuals who received doxyPEP exhibited lower chlamydia (RR, 0.45; P P = .03), but higher gonorrhea positivity (RR, 1.97; P

IN PRACTICE:

“Our data represent early estimates of the association between receipt of doxyPEP and decreases in STI incidence in clinical practice and highlight the potential benefits of doxyPEP implementation for reducing STIs in sexual networks of people using HIV PrEP,” the authors wrote.

SOURCE:

The study was led by Michael W. Traeger, PhD, Department of Population Medicine, Harvard Pilgrim Health Care Institute in Boston. It was published online on January 6 in JAMA Internal Medicine.

LIMITATIONS:

The most important limitation is that early adopters of doxyPEP among HIV PrEP users may not be representative of all potential beneficiaries, with an under representation of Black individuals. Changes in sexual behavior during the study period could have influenced STI incidence. Finally, due to the observational nature of the study, the causal effect could not be directly assessed.

DISCLOSURES:

The study was supported by the National Institutes of Health. Four authors reported receiving grants, speaker honoraria, and travel costs from Gilead Sciences, Merck, and National Institutes of Health.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.