High Burden of Sexually Transmitted Infections Among Pre-exposure Prophylaxis (PrEP) Users: Testing and Prevention...

Area of Science:

• Infectious Diseases
• Public Health
• Sexual Health

Background:

• Pre-exposure prophylaxis (PrEP) is effective for HIV prevention but does not prevent other sexually transmitted infections (STIs).
• Increasing STI rates among PrEP users necessitate integrated sexual health strategies.
• Risk compensation and the need for comprehensive prevention are key concerns.

Purpose of the Study:

• To assess STI prevalence, anatomical distribution, and behavioral determinants in PrEP users in Spain.
• To identify factors associated with STI diagnosis in this population.
• To inform the development of integrated sexual health strategies within PrEP programs.

Main Methods:

• Retrospective observational study of 724 individuals on daily TDF/FTC in Madrid (March-October 2023).
• Data collected via medical records and electronic questionnaires (sociodemographic, behavioral, microbiological).
• Routine quarterly PCR screening for Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, and Trichomonas vaginalis from anal, pharyngeal, and urine samples.

Main Results:

• 65.7% of participants were diagnosed with at least one STI during follow-up (968 episodes, 1271 detections).
• Neisseria gonorrhoeae (35.3%) and Chlamydia trachomatis (30.3%) were most common; most infections were anal (55.1%).
• Younger age, more partners, and chemsex were associated with STI diagnosis; only one HIV acquisition (0.1%).

Conclusions:

• High burden of bacterial STIs, especially at anal sites, in PrEP users.
• Supports systematic multisite testing, adherence support, and behavioral interventions.
• Recommends considering doxycycline post-exposure prophylaxis and future gonococcal vaccines within PrEP programs.