Many people who are at risk of HIV remain unprotected despite clear indications for pre-exposure prophylaxis (PrEP), revealing missed prevention opportunities, according to new research presented at IDWeek 2025.
A team of researchers, led by Richard A. Elion, MD, Trio Health, Louisville, Colorado, assessed the PrEP cascade using the Trio Health Database from 2016 onward. They evaluated more than 164,000 people without HIV who were PrEP-eligible and had at least two medical visits.
Of the people identified, 74% (n=121,472) were considered “PrEP indicated.” The indication was based on sexually transmitted infection (STI) testing (64%), HIV testing (58%), STI diagnoses (31%), post-exposure prophylaxis (PEP) use (2%), and ICD codes that indicated sexual behaviors associated with HIV acquisition (SBawH; 29%), and prevention counseling (12%).
In the PrEP indicated group, just 17% received a prescription for PrEP (emtricitabine/tenofovir or cabotegravir), while 83% went without a prescription. Most of the people who were given a prescription began PrEP (85%).
When assessing PrEP adherence, the researchers observed gaps (no drug supply for >90 days) in PrEP among 83% of the people and discontinuations in 19%.
The researchers further investigated and expanded the PrEP criteria through a sensitivity analysis. The criteria included the following: pregnancy testing, STI symptoms, drug dependency, and family planning. By adding these, the PrEP indicated group increased to 81%—highlighting that even more people could be at risk and are not receiving PrEP. Prescriptions were more commonly given to people who had medical codes for SBawH (45%) and prevention counseling (22%).
In addition, the analysis also revealed that 857 people acquired HIV during follow-up. Among this group, prescriptions were most likely given to those with STI diagnoses (31%) and those who had HIV testing (58%).
Despite having a PrEP prescription, adherence remained poor, with 83% of people having gaps in care. The researchers identified limitations in the study, such as reliance on clinical codes that may be incomplete or inconsistent. “Identification of robust clinical and behavioral factors could facilitate effective PrEP intervention, strengthening prevention efforts,” they noted.
Reference
Elion RA, Mayer KH, Scott R, et al. PrEP utilization patterns and indications in a cohort of HIV-negative individuals. P-328. Presented at: IDWeek 2025, Oct. 19-22, 2025, Atlanta, GA.
