Expectations of preventative benefits and risk behaviors in a randomized trial evaluating oral HIV preexposure prophylaxis candidates.

When participants enrolled in an HIV prevention trial hold a preventive misconception (PM) - expectations that experimental interventions will confer protection from HIV infection - they may engage in behaviors that increase their risk of acquiring HIV. This can raise ethical concerns about whether those enrolled in the trial understand the nature of participation and their safety. Consequently, we systematically evaluated the prevalence of PM and its association with risk behaviors in a trial examining three candidate regimens for oral HIV pre-exposure prophylaxis in which all participants received at least one antiretroviral agent. Overall, trial participants exhibited relatively high preventive expectations that may be associated with an increase in risk behaviors among men who have sex with men. In addition, we identified substantial site variability in PM that necessitates future research to uncover its source. This will allow appropriate measures to be taken to mitigate PM and help ensure that participants have an accurate understanding of the potential risks and benefits of trial participation throughout the course of a trial.