Not quite half of women who received HIV pre-exposure prophylaxis (PrEP) through a syringe services program for people who inject drugs were still on the daily pill six months later, according to a small study published in the Journal of Acquired Immune Deficiency Syndrome.

The persistent racial PrEP gap between Black women and their white and Latina counterparts showed its face again, but women who’d experienced sexual assault were nearly six times as likely to stay on the pills, offering what Alexis Ross, PhD, of Drexel University in Philadelphia, and colleagues suggested was evidence against the assumption that people who inject drugs don’t want and won’t take HIV prevention pills.

In Project SHE, Ross and her colleagues recruited 95 HIV-negative women who inject drugs who received syringe services at Prevention Point Philadelphia between April 2018 and March 2019. All were at least 18 years old. The median age of the women was 36, and 70% were white. Nearly two thirds identified as currently homeless; others said their housing was precarious. Most earned less than $5,000 a year. HIV acquisition was a real risk for the women as well: 70% of the women engaged in transactional sex or used condoms inconsistently. Women interested in becoming pregnant or who became pregnant were excluded from the study, as it was conducted before the Department of Health and Human Services updated its perinatal guidelines to include Truvada (emtricitabine/tenofovir disoproxil fumarate) PrEP for pregnant people.

Sixty-three of the women agreed to start on Truvada, and navigation services helped them  access the pills through their public or private insurance or through patient access programs. Women had the option of receiving a paper PrEP prescription or having their medication delivered to Prevention Point for pickup there. The participants could stop PrEP at any time.

The women were followed for 24 weeks. Clinical assessments and lab work (which included pregnancy tests, HIV tests, other sexually transmitted infection tests and tests for side effects) were performed at week 1 (baseline), week 3, week 12 and week 24. At each follow-up visit, the researchers asked the women whether they were still taking PrEP and also took urine samples to check adherence. Finally, they asked the women whether they liked taking PrEP and whether taking it was compatible with their lifestyles.

By week 24, 42 women (44%) were still on PrEP. Two of those women acquired HIV during the next 24 weeks—one at week 12 and the other at week 24. Both had urine tests that confirmed inconsistent PrEP use.

There were some differences by race. Black women were 11% less likely than white women to start PrEP and 12% less likely to still be on PrEP at the end of the trial. Interestingly, Latinas were 22% less likely to start PrEP, but once they did, they were 59% more likely than their white counterparts to still be on it at the end of the study.

Women were nearly six times as likely to still be on PrEP at the end of the trial if they’d experienced sexual assault and three times as likely to still be on it if they used condoms inconsistently. Women who more frequently interacted with Prevention Point were 85% more likely to still be on PrEP at the end of the study period.

“Our findings challenge the idea that daily PrEP is not a viable HIV prevention tool for [people who inject drugs],” wrote Ross and colleagues. “Rather, we demonstrate that [syringe service programs] are promising locations to reach women who inject drugs who would benefit from and are interested in receiving PrEP in this setting.”

Click here to read the study abstract.

Click here to read more about HIV and people who inject drugs.