It’s a common belief that daily pre-exposure prophylaxis (PrEP) pills do not protect cisgender women as well as gay and bisexual men. Studies have found that tenofovir levels are lower in vaginal and cervical tissues compared with rectal tissue, suggesting that women may need to take PrEP more consistently. But further analysis shows that protection depends on adherence, not biological factors.

 

A mathematical modeling analysis of real-world data from 11 post-marketing studies, mostly conducted in Africa, found that tenofovir disoproxil fumarate/ emtricitabine (Truvada or generic equivalents) was highly effective for women who took at least four doses per week. None of the women who took PrEP pills every day acquired HIV. Among those who took four to six doses per week, only one seroconverted, similar to the incidence rate for gay men. Although daily adherence is optimal, a minimum of four doses per week “is expected to provide effective protection for most females,” the researchers concluded. However, less than 40% of the women in the studies achieved this level of adherence, suggesting that long-acting injectable PrEP may be a better option for some cisgender women.

 

“By combining data from several moderately sized studies, we have revealed a trend in prevention-effective use that suggests brief dosing inter- ruptions should not stop cisgender women from experiencing the potentially life-changing benefits of oral PrEP,” says National Institute of Allergy and Infectious Diseases director Jeanne Marrazzo, MD, MPH.