Incidence and Predictors of Chlamydia, Gonorrhea and Trichomonas among a Prospective Cohort of Cisgender Female Sex Workers in Baltimore, Maryland

Background Cisgender female sex workers (CFSWs) have elevated rates of sexually transmitted infections (STI) yet are underrepresented in targeted programming and research in the United States. We examined the prevalence, incidence and predictors of chlamydia, gonorrhea, and trichomonas infection among CFSW. Methods Two hundred fifty street-based CFSWs were recruited into a prospective observational cohort in Baltimore, Maryland using targeted sampling in 2016 to 2017 and completed surveys and STI testing at baseline, 3, 6, 9, and 12 months. Cox proportional hazards regression was used to model the predictors of STI. Results Mean age was 36 years, and 66.5% of respondents were white. Baseline prevalence of chlamydia, gonorrhea, trichomonas was 10.5%, 12.6%, and 48.5%, respectively. The incidence of chlamydia, gonorrhea, and trichomonas was 14.3, 19.3, 69.1 per 100 person-years. Over one year of observation, past year sex work initiation predicted both chlamydia incidence (adjusted hazard ratio [aHR], 2.7; 95% confidence interval [CI], 1.3-6.0) and gonorrhea incidence (aHR, 1.7; 95% CI, 1.0-2.8). Client sexual violence predicted gonorrhea incidence (aHR, 2.9; 95% CI, 1.2-7.1) and having female sexual partners predicted trichomonas incidence (aHR, 3.4; 95% CI, 1.3-8.5). Having a usual health care provider (aHR, 0.6; 95% CI, 0.5-0.7) was inversely associated with trichomonas. Conclusions In this study of urban US street-based CFSW, interpersonal and structural factors differentially predicted STIs, and infection rates remained elevated through follow-up despite regular testing, notification, and treatment referral. Focused and multifaceted interventions for sex workers and their sexual partners are urgently needed.