High Baseline Prevalence and Stable Incidence of Chlamydia and Gonorrhea During the First Year of HIV Pre-Exposure Prophylaxis: A Multicenter Italian Cohort Study
Chiara Fusetti, Roberto Rossotti, Serena Reato, Nicholas Brian Bana, Letizia Oreni, Chiara Baiguera, Andrea Giacomelli, Elena Simoncini, Gabriele Cavazza, Massimo Puoti, Andrea Gori, Davide MoscheseIntroduction:
Concerns persist that HIV pre-exposure prophylaxis (PrEP) may be associated with increased sexually transmitted infections (STIs), but longitudinal data incorporating the pre-PrEP period and standardized screening remain limited.
Methods:
We conducted a retrospective cohort study of individuals initiating oral emtricitabine/tenofovir disoproxil fumarate PrEP at two STI clinics in Milan, Italy (2018–2024). Participants underwent baseline and quarterly screening (pharyngeal, anal, vaginal swabs and urine NAATs) for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG). We estimated baseline prevalence and interval-specific conditional cumulative incidence (CCI) across 0–3, 3–6, 6–9, and 9–12 months intervals, and described symptomatic and recurrent diagnoses. Finally, we evaluated STI trends across three calendar periods: 2018–2019, 2020–2021, and 2022–2024.
Results:
A total of 1,087 individuals were included (median age 35 years [IQR 30–41]); most were cisgender GBMSM (98.4%). At baseline, 15% (163/1,087) had at least one CT/NG infection. During follow-up, 516 new diagnoses occurred in 359 individuals (33%). Interval-specific CCIs for any CT/NG infection were 13.5%, 15.2%, 17.7%, and 12.7% across the four intervals. The majority of infections were asymptomatic.
No substantial differences in STI trends were observed across the three calendar periods.
Conclusions:
In this real-world PrEP cohort undergoing quarterly NAAT screening, CT/NG diagnoses were common at baseline and maintained high but stable incidence during the first year after PrEP initiation, with no clear upward trend over time.