Decision-making regarding condom use among daily and event-driven users of pre-exposure prophylaxis in the Netherlands - a mixed-methods analysis.

OBJECTIVE To explore the frequency of and reasons for using condoms among men who have sex with men (MSM) on PrEP. DESIGN We analyzed quantitative app-based diary data on daily sexual practices (August 2015-February 2019) and qualitative in-depth interviews (IDIs) among MSM using daily (dPrEP) and event-driven PrEP (edPrEP) in the Amsterdam PrEP demonstration project. METHODS Participants could report daily about sex acts, PrEP use and condom use per partner type (steady (SP) and casual partners (CPs)). We examined four strategies of PrEP and condom use: (1) PrEP-only; (2) PrEP and condoms; (3) condoms-only; and (4) neither strategy. We compared the proportions of sex acts per strategy between PrEP regimens. In 43 IDIs, we explored motives for implementing each strategy. RESULTS 352 participants reported 48,949 anal sex acts. PrEP-only was the most common strategy employed with any partner type (81%, n = 39,650/48,949) and was motivated by anticipating more pleasurable sex, STI's perceived curability, and habituation to condomless sex. Combining PrEP and condoms was more often chosen for sex acts with CPs (18%; n = 6,829/37,317) than with SPs (5%; n = 614/11,632) and was linked to e.g., higher STI/HIV perceived vulnerability and avoidance of PrEP-disclosure. Condoms-only was uncommon but occurred particularly among edPrEP users (4%; n = 379/8,695). Applying neither strategy was common among edPrEP users with SPs (25%; n = 538/2,122) and was motivated by low perceived HIV-risk. CONCLUSIONS Condoms remain a viable option for PrEP users in certain settings. Condoms were applied in higher-risk settings, to avoid PrEP disclosure, or as substitute for PrEP, especially among edPrEP users.