Interest in event-driven PrEP among men who have sex with men using daily PrEP in Mexico in 2019-2020: a cross-sectional assessment in a large-scale demonstration project.

This study aimed to evaluate the interest in event-driven PrEP (ED-PrEP) among men who have sex with men (MSM) using daily PrEP in Mexico's PrEP demonstration project between 2019 and 2020. We compared participants interested or not in ED-PrEP during their first-month visit and identified associated factors. Of 1,021 MSM attending their first-month visit, 7% had previous knowledge of ED-PrEP, but 40% were interested in ED-PrEP. However, over 50% perceived the scheme as less protective than daily PrEP. Having doubts about ED-PrEP's level of protection was related to less interest in the scheme (aOR = 0.11; CI = 0.07-0.18), just like reporting perceived barriers such as having frequent sex (aOR = 0.06; CI = 0.03-0.14), unplanned sex (aOR = 0.17; CI = 0.11-0.27), forgetting the medicine (aOR = 0.06; CI = 0.03-0.12), or difficulty carrying the medicine (aOR =   0.13; CI = 0.07-0.25). Finally, reporting not taking PrEP for >20 days in the last month (aOR = 0.05; CI = 0.01-0.27) diminished interest in ED-PrEP. In conclusion, few MSM daily PrEP users knew about ED-PrEP yet many were interested in it, suggesting the importance of awareness campaigns regarding ED-PrEP's effectiveness. The lack of interest in ED-PrEP among participants with poor adherence to daily PrEP indicates that they might prefer long-acting PrEP or HIV prevention strategies without medication.