People who use pre-exposure prophylaxis (PrEP) for HIV-1 prevention were tested for sexually transmitted infections (STIs) more frequently than before they began PrEP. Yet, only about a third of people followed the recommended testing schedule.
These findings are from a real-world study presented at IDWeek 2025 by Xiwen Huang, PhD, of Gilead Sciences, Inc. Dr. Huang and colleagues examined testing patterns among people living in the United States.
Current Centers for Disease Control and Prevention guidelines recommend routine STI testing every 3-6 months for people receiving PrEP.
Using HealthVerity data, the researchers identified adults aged 18 and older who were newly prescribed any PrEP regimen between October 2020 and December 2023 (n=42,408). Researchers assessed testing and prevalence of chlamydia, gonorrhea, and syphilis at 12 months pre- and post-PrEP initiation. Testing frequency was categorized as every 3 months, greater than 3-6 months, greater than 6-9 months, and greater than 9 months.
Huang reported that STI testing rates increased from 26% pre-PrEP to 47% post-PrEP among the study population. Within 30 days after PrEP initiation, 27% were tested. However, just 33% of all PrEP users received STI testing within the recommended 6-month period. Just over two-thirds (67%) of the study population were tested greater than 6 months or not at all.
Testing increased following the start of PrEP, with the number of people who received at least two tests going from 4,496 to 15,378. Moreover, STI prevalence increased from pre-PrEP to post-PrEP use (12% vs 18%, respectively).
The study also uncovered several factors that influenced testing frequency. For instance, the lowest testing frequencies were among people aged 45 or older, those living in the South or Midwest, and those with commercial insurance. Even with the start of PrEP, STI testing remained lowest in the South and in the 45 and older age group. All other populations increased testing to about 30% every 3 months.
With the field of PrEP evolving—regimens moving from daily pills to long-acting injectables—the researchers called for educational and structural interventions to help increase adherence to STI testing recommendations.
Reference
Huang X, Yang J, Gemson E, et al. Real-world sexually transmitted infection (STI) testing patterns among individuals using pre-exposure prophylaxis (PrEP) for HIV-1 prevention in the United States. P-287. Presented at: IDWeek 2025, Oct. 19-22, 2025, Atlanta, GA.
