Coverage of Sex Acts by Event-Driven Pre-exposure Prophylaxis: A Sub-Study of the ANRS IPERGAY Trial.

: We assessed the coverage of sex acts by event-driven pre-exposure prophylaxis (ED-PrEP) over a 2-month period in 54 participants in the open label phase of the ANRS Ipergay trial. Participants received an electronic monitoring system device to record bottle openings. Self-questionnaires collected daily information on PrEP intake and sexual behavior. Intake was also estimated through returned pill counts. Full coverage of sex acts was defined as at least one pill taken both within 24 h before and within 48 h following sex. There was a strong correlation (r =  - 0.92) between the number of bottle openings and returned pill counts. During the study, 42 participants (78%) practiced ED-PrEP and 12 (22%) daily PrEP with bottle openings at least 5 days/week whatever their sexual activity. Out of the 154 reported receptive anal sex acts, 81% were condomless: among them, PrEP coverage was hight: 97% among those practicing daily PrEP and 82% among those using ED-PrEP.