Incident and Recurrent Sexually Transmitted Infections by Gender Identity Among Sex Workers on HIV Pre-Exposure Prophylaxis: A Prospective Cohort Study.

BACKGROUND

Sex workers on HIV pre-exposure prophylaxis (PrEP) experience high bacterial sexually transmitted infection (STI) rates. We assessed associations between gender identity and first/recurrent STI incidence to inform risk-stratified screening.

METHODS

This prospective cohort study (Madrid, 2022-2026) evaluated sex workers initiating PrEP. Participants underwent quarterly screening for Neisseria gonorrhoeae, Chlamydia trachomatis, and Treponema pallidum. We used Cox and Prentice-Williams-Peterson models to evaluate first and recurrent STIs, adjusting for confounders.

RESULTS

We included 147 sex workers (71 transgender women, 48 cisgender men, 28 cisgender women) with ≥3 months follow-up and ≥1 STI screening. First STI incidence was 5.14/100 person-months (cisgender men: 6.90; cisgender women: 2.13). Recurrent STI incidence was 3.26/100 person-months. Most incident STIs (93.1%) were asymptomatic. In multivariable analyses (reference: cisgender women), cisgender men had higher hazards for first (adjusted hazard ratio [aHR], 3.20; 95% CI, 1.47-6.99) and recurrent STIs (aHR, 4.04; 95% CI, 1.83-8.95). Transgender women also had higher hazards for first (aHR, 2.08; 95% CI, 1.02-4.22) and recurrent STIs (aHR, 2.25; 95% CI, 1.10-4.61).

CONCLUSIONS

STI incidence during PrEP differs by gender identity, being highest in cisgender men and lowest in cisgender women. These findings support evaluating risk-stratified screening approaches over uniform quarterly guidelines.