MyPEEPS Mobile Plus: A Multi-Level HIV Prevention Intervention for Young Men - Men who have sex with men have the highest rates of HIV diagnoses in the United States, illustrating the need for efficacious HIV prevention tools for these populations. In response to the burgeoning HIV epidemic in young men who have sex with men, our study team adapted the theory-driven, group-level, evidence-based MyPEEPS intervention for young men (R34MH079707; PI: Garofalo) into an mHealth intervention, MyPEEPS Mobile, to overcome challenges of an in-person group intervention. MyPEEPS Mobile is a sexual health intervention delivered through peer avatars whose personal backgrounds and sexual risk scenarios are composites derived from formative research among young men, which identified personal, family-based, and relational challenges influencing sexual health. The MyPEEPS Mobile Trial data have shown evidence of efficacy, feasibility, acceptability, and high satisfaction by participants 13-18 years of age. Despite very promising results, pre-exposure prophylaxis (PrEP) initiation to date over the course of the study has been extremely low in our sample (3%), which we partially attribute to a dearth of information on pre-exposure prophylaxis content in MyPEEPS Mobile and the very young age (13-18 years) of our study participants, for whom pre-exposure prophylaxis was not approved at the time of data collection. In response, our study team proposes to expand MyPEEPS Mobile to develop MyPEEPS Mobile Plus, a multi-level intervention comprised of MyPEEPS Mobile with added pre-exposure prophylaxis content (based upon expert advisory and youth feedback) + pre-exposure prophylaxis E-Peer Navigation to overcome the challenges of pre-exposure prophylaxis initiation, adherence, and persistence among young men. Peer navigation is an evidence-based, widely recommended intervention for reaching youth and men for HIV-related care outcomes, with evidence of acceptability among young men for pre-exposure prophylaxis. Peer navigation addresses common reasons for failing to begin or maintain PrEP use, including low perceived risk, structural or logistic barriers to care engagement, and anticipated side effects. Relative to in-person and group-based HIV prevention programs, behavioral interventions with digital and virtual components can have vast reach and present unique potential to rapidly scale delivery to very large and hidden groups. Therefore, we propose to conduct a randomized controlled trial to test the efficacy of MyPEEPS Mobile Plus (a multi-level intervention comprised of MyPEEPS Mobile + pre-exposure prophylaxis E-Peer Navigation) for promoting initiation, adherence, and persistence of pre-exposure prophylaxis and decreased HIV risk behavior in young men. Building upon our team’s demonstrated ability to enroll large numbers of young men and extensive experience developing mobile health interventions, the proposed study will test the efficacy of this expanded, multi-level mobile HIV prevention intervention emphasizing pre-exposure prophylaxis. If efficacious, it will increase pre-exposure prophylaxis initiation, adherence, and persistence and decrease overall HIV risk in young men in the US.