Background
Doxycycline post-exposure prophylaxis (doxyPEP) is a biomedical intervention that can reduce the risk of bacterial sexually transmitted infections (STIs) among individuals assigned male sex at birth. However, its real-world implementation patterns and barriers to timely access are poorly understood. We evaluated the uptake of doxyPEP across a nationwide sample of male veterans with a bacterial STI across different regions and subgroups, and identified factors associated with time to prescription.
Methods
We conducted a retrospective cohort study of male veterans with at least one incident bacterial STI (gonorrhea, chlamydia, and/or syphilis, defined as an index STI) diagnosed within the US Veterans Affairs health system between January 1, 2022 and September 30, 2025. Our primary outcome of interest was any prescription for doxyPEP. We evaluated doxyPEP use by age, race, HIV status, pre-exposure prophylaxis (PrEP) use, and region using multivariate logistic regression. We evaluated time to doxyPEP after an index STI using multivariate quantile regression.
Results
Of 29,009 male veterans diagnosed with a bacterial STI, 2,444 (8.4%) were prescribed doxyPEP, of which 37% had HIV, 37% were on PrEP, and the median age was 38. The US South accounted for 55% of all STI diagnoses and 45% of all doxyPEP prescriptions. Veterans in the Northeast (aOR 1.51, 95% CI 1.27—1.81) and West (aOR 2.29, 95% CI 2.04—2.57) were more likely to receive doxyPEP compared with those in the South. DoxyPEP was associated with PrEP use (aOR 23.82, 95% CI 20.94—27.11) and HIV infection (aOR 7.21, 95% CI 6.36—8.17). White veterans had lower odds of receiving doxyPEP compared with Black veterans (aOR 0.87, 95% CI 0.77—0.98), as were veterans aged >50 (aOR 0.54, 95% CI 0.46—0.63) compared with those aged 18-30. The median time from index STI to doxyPEP prescription was 13 months. Those on PrEP and with HIV experienced a median delay of doxyPEP uptake of 4.58 and 4.26 months longer, respectively, compared to those without those characteristics.
Conclusions
Although the US South accounted for the largest proportion of doxyPEP prescriptions, uptake relative to STI burden was lower than in the Northeast and West. Despite higher doxyPEP uptake among veterans on PrEP or with HIV, these groups experienced significant delays in doxyPEP initiation, suggesting missed opportunities for timely prevention. These findings can help guide interventions and implementation strategies to expand uptake and reduce delays in providing doxyPEP.