On-demand pre-exposure prophylaxis (PrEP) using tenofovir disoproxil fumarate/emtricitabine (Truvada or generics) before and after sex remained as effective as once-daily pills over eight years of follow-up if taken as directed. The PREVENIR trial compared once-daily and intermittent PrEP in more than 3,000 HIV-negative gay and bisexual men and transgender women in Paris. In 2022, the researchers reported that HIV incidence was low and comparable in both groups; follow-up continued through May 2025. HIV incidence remained low overall, at 0.99 cases per 1,000 person-years. There were three cases among participants who used daily PrEP, seven among those who used on-demand PrEP and three among those who switched between the two regimens. These participants were not taking PrEP at the time of HIV acquisition or showed evidence of poor adherence. HIV incidence declined by 33% among gay and bisexual men born in France during the follow-up period but rose by 73% among those born elsewhere, underscoring the need for improved access to PrEP.