Preferences for daily or intermittent pre-exposure prophylaxis regimens and ability to anticipate sex among HIV uninfected members of Kenyan HIV serodiscordant couples

Intermittent dosing for pre-exposure prophylaxis (PrEP) has been proposed as an alternative to daily PrEP to reduce cost and patient drug exposure and to improve adherence. One possible dosing regimen is pre-intercourse PrEP, which requires anticipating sex in advance. We examined preferences for daily versus pre-intercourse PrEP and ability to anticipate sex among 310 HIV uninfected members of HIV serodiscordant heterosexual couples in Thika, Kenya, with high HIV knowledge and experience with daily PrEP use in a clinical trial setting. Preferences were evenly split between daily PrEP (47.4 %) and pre-intercourse PrEP (50.7 %). Participants were more likely to prefer daily PrEP if they reported unprotected sex during the prior month (adjusted prevalence ratio [aPR] 1.48, 95 % CI 1.20-1.81) or <80 % adherence to study drug (aPR 1.50, 95 % CI 1.25-1.79), and were less likely to prefer daily PrEP if sex was usually planned, versus spontaneous (aPR 0.76, 95 % CI 0.61-0.96). A minority (24.2 %) reported anticipating sex >3 h in advance, with younger participants being less likely to do so (aPR 0.43, 95 % CI 0.23-0.83 for ages 18-29 vs. ≥40). Findings suggest that intermittent PrEP could be a popular option in this population, but that optimal adherence and sufficient drug levels might be challenging with a pre-intercourse regimen.