Despite dramatic improvements in the biomedical treatments for both preventing and treating HIV infection, American adolescents are increasingly likely to become infected, are not using ARV for prevention or treatment, and are not learning they are HIV seropositive when they have become infected. America's HIV epidemic among youth has more than doubled in the last 15 years and now represents 26% of the epidemic. These youth are not found in every community - geography is destiny in HIV prevention (www.AIDSVu.com). YLH are concentrated along I-95 on the East Coast, in Southern cities, and West Coast. Given the distribution of emerging infections, we have chosen two HIV epicenters, Los Angeles (LA) and New Orleans, to test a strategy to identify, link to care, and intervene to prevent HIV. Even in those two areas, adolescent HIV will not be found in every neighborhood. In LA, six neighborhoods account for 80% of HIV cases in the County - reflecting the concentration of HIV within neighborhoods and settings. In each epicenter, the youth at highest risk of infection will be gay, bisexual, and transgendered youth (GBTY), especially those who are Black and Latino. Homeless youth will also be at highest risk: the last HIV seroprevalence study showed a 5.3% rate among homeless youth. Youth who are incarcerated are at higher risk of being in risk setting and will be targeted for recruitment to this study. Having a sexual orientation as GBTY is highly stigmatizing and youth are developmentally challenged about who, when, how, and what to disclose their sexual orientation of HIV status to their families and their peers. Unfortunately 42% of GBTY's parents eject their children when children disclose being GBTY resulting in 40% of homeless youth being GBTY. Homeless GBTY had a seroprevalence of 24.8% in 1989.

The sites that typically serve GBTY and High Risk Youth (HRY) (gay-identified CBO and homeless shelters) in HIV epicenters only provide HIV testing to about 10% of youth currently. To effectively stop HIV among youth, a more integrated strategy that tests for HIV and STIs repeatedly, links youth to care, and helps youth access all HIV prevention strategies, including Pre Exposure Prophylaxis (PrEP) and Post Exposure Prophylaxis (PEP), is needed. The proposed research will test such a strategy.

To eliminate HIV among youth, scalable, efficacious, and cost-effective strategies are needed to optimize the HIV Prevention Continuum of repeat testing, linkage to biomedical and behavioral prevention, and retention and adherence over time to PrEP, PEP, condom use and reduced number of partners. The HIV Prevention Continuum is a framework for guiding prevention efforts.

Advances in mobile and social media technologies have created opportunities to engage and intervene with large numbers of youth at relatively low costs, technologies that permeate their daily routines. This study will use two primary technology platforms: text-messaging and social media. Text-messaging, email, internet and social media use are nearly universal among youth, including homeless youth. Rates of mobile phone, smartphone, and internet usage increase with age, and nearly 90% of young adolescents (age 13-17) having a mobile phone. Texting is particularly important for adolescents; 90% of those with phones text, typically receiving and sending 30 texts each day. Similarly, over 90% of adolescents under age 18 go online daily, more than half several times a day, which is facilitated the three quarters with smartphones that are crossing the digital divide. African-American and Latino youth have higher rates of smartphone and internet use than White. All of these rates increase for adolescents 18 and over. Ownership, access, and use rates are similar for homeless youth, although with less frequency and some inconsistency. Much of this online activity is driven by social media, particularly via smartphones, with over 70% of adolescents under 18, for example, using Facebook and other applications (about half also use Instagram and Snapchat).

The interventions proposed in this study will use text-messaging and social media to engage "youth where they're at" in the digital environment as preferences and functions change. Importantly, mobile phones continue to receive text-messages even when data plans run out of credit to use apps' and mobile-web browsers or send text-messages. Therefore, the core component our technology strategy will be text-messaging in the Automated Messaging and Monitoring Intervention (AMMI) for all youth in the cohort. Social media will be used by Peer Supporters to engage and support their peers through online discussion boards while Coaches will engage through social media, text-messaging, and voice and video-chats (however most acceptable to individual youth), as well as in person contacts. Mobile and social media technology-based engagement, retention, prevention, and mobilization strategies are likely to be scalable. This study will test whether they are also efficacious and cost-effective.

Upon study launch in April 2017, decisions were made with the funder to provide three-site STI testing at baseline and every follow-up assessment. In December 2018, the funder changed priorities and reduced support for STI testing to rectal testing only at baseline, 12- and 24-month follow-up, unless the participant displays STI symptoms or requests testing at other follow-up assessments. The funder has also decided to terminate the intervention and follow-up assessments at 12 months, rather than 24 months, for youth who are at lower behavioral risk for HIV acquisition.