ABSTRACT Cook County Health Despite advances in Human Immunodeficiency Virus (HIV) diagnostics, care, and prevention strategies, infection rates continue to rise across the United States, particularly the medically underserved of low socio- economic status, sexual and gender minority groups, and/or racial/ethnic minority constituency, and/or substance abusing youth. There is an urgent need to reduce the number of new HIV infections among at-risk youth and improvements in numbers across the HIV care continuum. The Adolescent and Young Adult Research (AYAR) at Core Consortium will participate in the Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN) as it has since 2001. The AYAR consortium will continue to work collaboratively within the ATN structure to assist in the development and implementation of interventional studies that address the ATN scientific priority areas across the HIV/AIDS prevention and treatment continuum among adolescents and young adults (ages 13-24) through primary, secondary, and tertiary prevention approaches. The consortium's HIV experienced, multidisciplinary clinical and community-based staff will be responsible for ATN subject recruitment, retention, and safety in our well-established adolescent HIV care program and consortium network, with the use of innovative methods, to reach the most underserved and highest risk communities of the Chicagoland area. They will continue to improve upon its leadership model with meaningful and sustainable community engagement efforts, targeting high HIV prevalence areas, leveraging local health departments and community partners in promoting and engaging youth in health care and research directed at ending the HIV epidemic. The consortium will maintain and establish new Community Based Organization (CBO) partnerships and conduct community outreach activities in targeted areas within Cook County's high HIV-affected areas and with a focus on sexual minority groups. AYAR will continue to support CBOs via in- person or virtual meetings and events, educational sessions, and sexually transmitted infection (STI) testing. AYAR will continue to maintain an active research Youth Advisory Board (YAB) with regular meetings via in person or virtual means. The consortium will increase sexual health education and awareness of HIV prevention strategies and assist with linkage to care for pre-exposure prophylaxis (PrEP) and HIV care. The AYAR will provide site, laboratory, pharmacy, and community capacities, to support impactful research studies identified by the ATN Executive Committee and Scientific Leadership Group, in collaboration with the Operations and Collaborations Center (OCC). Our investigative team has decades of experience with recruitment, prevention, and care of at-risk youth and large-scale longitudinal cohort studies. This study will capitalize upon productive existing partnerships to articulate the drivers of the ongoing HIV epidemic among the most vulnerable populati...