Interest and disparities in awareness and uptake of doxyPEP among U.S. MSM living with HIV

Objective: The CDC recommends doxycycline post-exposure prophylaxis (doxyPEP) for men who have sex with men (MSM) with a bacterial sexually transmitted infection (bSTI) in the past year. This study explored determinants of doxyPEP awareness and uptake, and associations with HIV care outcomes, among U.S. MSM living with HIV. Design: Cross-sectional study. Methods: From 10/2023-10/2024, we enrolled 827 MSM living with HIV from 46 states, Washington, D.C., and Puerto Rico via a popular geospatial networking app. Adjusted multivariable logistic regression examined determinants of doxyPEP awareness/use and associations with HIV treatment adherence, viral suppression, and care engagement. Results: Among 827 participants, 13% were currently taking doxyPEP, 46% were aware of doxyPEP but not prescribed it, and 41% had not heard of it. Of 360 participants CDC-eligible for doxyPEP, 20% were prescribed it, 49% had heard of it but were not on it, and 31% were unaware, 95% of whom expressed interest. Neither awareness nor use of doxyPEP was associated with HIV care outcomes. Both awareness and uptake of doxyPEP were higher among participants with a recent bSTI (adjusted odds ratio (aOR)=1.15, 95%CI: 1.06-1.25; aOR=1.11, 95%CI: 1.05-1.17, respectively) and lower in the U.S. Midwest, Mountain, and South regions (inverse-variance weighted average (IVW-Avg) aOR=0.81, 95%CI: 0.76-0.86; IVW-Avg aOR=0.86, 95%CI: 0.82-0.90, respectively) relative to Pacific states. Conclusions: High doxyPEP interest underscores unmet demand in integrated HIV/sexual health care. Sociodemographic and geographic disparities in doxyPEP implementation necessitate targeted interventions for MSM living with HIV to optimize impact on the bSTI epidemic.