Choosing between daily and event-driven Pre-Exposure Prophylaxis: results of a Belgian PrEP demonstration project

BACKGROUND: Daily and event-driven Pre-Exposure Prophylaxis (PrEP) are efficacious in reducing HIV transmission among men who have sex with men (MSM). We analysed baseline data from a PrEP demonstration project 'Be-PrEP-ared' in Antwerp, Belgium to understand preferences for daily or event-driven PrEP among MSM at high risk for HIV, and factors influencing their initial choice.

METHODS: Cross-sectional data from an open-label prospective cohort study, using mixed methods. Participants who pre-registered online were screened for eligibility and tested for sexually transmitted infections (STIs). Eligible participants chose between daily and event-driven PrEP and reported on behavioural data through an electronic questionnaire. In-depth interviews were conducted with a selected sub-sample. Bivariate associations were examined between preferred PrEP regimens and sociodemographic factors, sexual behaviour, and STIs at screening.

RESULTS: In total, 200 participants were enrolled between October 2015 and December 2016. Self-reported levels of sexual risk-taking before enrolment were high. STI screening revealed that 39.5% had at least one bacterial STI. At baseline, 76.5% of participants preferred daily and 23.5% event-driven PrEP. Feeling able to anticipate HIV risk was the most frequent reason for preferring event-driven PrEP. Regimen choice was associated with sexual risk-taking behaviour in the last three months. Almost all participants (95.7%) considered it likely that they would change their dosing regimen the following year.

CONCLUSION: Event-driven PrEP was preferred by 23.5% of the participants, which better suits their preventive needs. Event-driven PrEP should be included in PrEP provision as a valuable alternative to daily PrEP for MSM at high risk for HIV.