The proposed MyPEEPS intervention for young transgender men is a novel and evidence-driven intervention using mobile technology to deliver HIV prevention information to high risk youth. The final product will be the basis for conducting a large-scale efficacy study in this population.

Transgender youth in the United States have unique health needs but often face barriers to accessing and receiving health care services which contribute to disparate health outcomes including high vulnerability to HIV and other sexually transmitted infections. Emerging evidence has begun to document HIV-related sexual risk among young transgender men (YTM), as well as low uptake of pre-exposure prophylaxis among those with indications, suggesting high vulnerability to HIV infection. Despite the high prevalence and increased risk of HIV in YTM who have sex with cisgender men, only one prior HIV prevention intervention has been developed to address the specific sexual health needs of YTM, which indicates a critical gap in HIV prevention science. In response to this need, and building off preliminary work, the investigators propose to develop a mobile intervention for YTM building on MyPEEPS Mobile, which was originally developed for very young sexual minority men. Central to this intervention is the premise that it will be delivered to youth during a developmental period that precedes or coincides with sexual debut, an important time for intervention, prior to or concurrent with initiation of high-risk behaviors.

Given both the gap in HIV prevention science and the lack of current targeted interventions, and building upon our multidisciplinary team's extensive experience in HIV prevention, mobile health (mHealth), behavioral interventions, randomized controlled trials, and transgender health, the investigators propose the following specific aims: 1) Using qualitative methodology, expert feedback, and usability assessments, develop MyPEEPS Mobile for YTM, 2) Conduct a pilot randomized controlled trial to examine the feasibility, acceptability, and preliminary efficacy of the revised MyPEEPS Mobile App in a sample of 80 YTM (15-25 years) and refine the study methods for a future efficacy trial, and 3) Assess predisposing, enabling, and reinforcing factors for MyPEEPS Mobile among YTM through theoretically-guided in depth interviews. The proposed MyPEEPS intervention for YTM will be the first study to develop and pilot a scaled-up, mobile HIV prevention intervention designed by, and piloted for, a diverse group of YTM. The final product of this study will be the basis for an R01 application to conduct a large-scale efficacy study for this population.

Inclusion Criteria:

To participate in any aspect of the study, participants must be:

• Between 15 and 25 years of age;
• Female sex assigned at birth;
• Identify as a transgender man or along the transmasculine spectrum (including a transmasculine non-binary gender; e.g., male, trans male, transmasculine gender non-binary);
• Understand and read English;
• Live within the US;
• Own a smartphone;
• Self-report condomless receptive anal or vaginal penile sex with either a cisgender male or transgender woman (e.g., individual designated or assigned male at birth) in the past year; and
• Self-report HIV-negative or unknown status.

Exclusion Criteria:

Youth are ineligible to participate in the trial if:

• HIV positive;
• Unable to provide informed consent due to severe mental or physical illness or substance intoxication at the time of enrollment;
• Concurrently enrolled in another HIV prevention study.

Identify as a transgender man or along the transmasculine spectrum (including a transmasculine non-binary gender; e.g., male, trans male, transmasculine gender non-binary);

While individual participant data (IPD) will not be shared, the results of the study will be shared at conferences such as the American Public Health Association annual meeting and Infectious Disease week; provide organizations that are influential in HIV public health practice (e.g., International AIDS Society) with an executive summary, press releases, and/or published papers; publish results in peer-reviewed academic journals; provide a lay summary for participants and community partners.

6 months