Abstract
BACKGROUND: HIV pre-exposure prophylaxis (PrEP) use has been linked with increases in sexually transmitted infection (STI) incidence. Despite efforts to expand PrEP uptake among young Black and Hispanic men who have sex with men (YBHMSM), little research has been done to understand the impact of PrEP on STI incidence within these communities. We examine the effect of PrEP use on gonorrhea and chlamydia (NG/CT) incidence, condom use, and external STI testing (ie, outside of study visits). METHODS: In a longitudinal cohort of HIV-negative YBHMSM (ages 16-24 years), we modeled the effect of PrEP use on study-external STI testing and number of condomless sex partners during the following 6 months using mixed-effects generalized linear models. We modeled the effect of PrEP use on NG/CT incidence using time-updated proportional hazard regression. RESULTS: While on PrEP compared with periods not on PrEP, participants reported on average 2.51 (adjusted beta; 95% CI, 1.51-3.51; P < .001) more condomless sex partners and were 2.28 (adjusted OR; 95% CI, 1.48-3.52; P < .001) times as likely to report study-external STI testing during the following 6 months. NG/CT incidence did not increase (adjusted HR, 0.75; 95% CI, 0.45-1.27; P = .286) while on PrEP compared with not on PrEP. CONCLUSIONS: Condomless sex increased with PrEP use; however, its potential to elevate STI acquisition or prolonged duration of infection may be mitigated by PrEP-associated routine testing. Efforts to expand PrEP uptake among YBHMSM appear unlikely to exacerbate the STI epidemic.