PROJECT SUMMARY In 2021, a Centers for Disease Control and Prevention HIV surveillance report indicated that Latinx communities accounted for 29% of new HIV diagnoses but comprised only 19% of the US population. In that same year, male-to-male sexual contact accounted for 67% of all new HIV diagnoses. These disparities in HIV cases have led to the designation of Latinx sexual and gender minority (LSGM) groups as priority populations in the Ending the HIV Epidemic (EHE) Plans, both nationally and locally, and in the Getting to Zero-Illinois Plan. Reasons for high HIV incidence and prevalence within LSGM communities are multifaceted and compounded by intersecting sexual and ethnic/racial identities. As preliminary work by our team and others has shown, lack of trust in health systems may reduce engagement and retention in HIV care and prevention services, including uptake and adherence to HIV pre-exposure prophylaxis (PrEP). Moreover, social and structural factors (e.g., racism, homophobia, stigma) may reinforce and perpetuate medical mistrust and misinformation in LSGM communities. Unfortunately, little is known about the mechanisms of medical mistrust and misinformation, particularly from the perspective of LSGM community members, and most research has focused on individual-level behavioral interventions, thereby neglecting to target medical mistrust as a social determinant of health. We believe that community- and structural-level interventions are needed to dismantle medical mistrust and misinformation, and to improve the state of HIV prevention, particularly for engagement in PrEP healthcare among LSGM. Leveraging our longstanding collaborations with local leaders in Latinx- focused research and service provision, including partnerships with our local health department, the long-term goal of this research is to prevent new HIV transmissions among LSGM by improving engagement in HIV prevention services, including PrEP. To accomplish this goal, we propose the following mixed methods research aims: 1) understand medical mistrust and misinformation and their impact on PrEP healthcare engagement (i.e., PrEP Stages of Change) from the perspectives of LSGM, HIV healthcare providers, and social service providers through interviews and a community-level survey; 2) utilize the ADAPT-ITT framework to select and tailor a CDC-designated, evidence-based intervention (EBI) for LSGM with a focus on medical mistrust, medical misinformation, and PrEP healthcare engagement using formative research, focus groups with LSGM, input from our community advisory board (The Chicago Queer Latina/x/o Collaborative), and feedback from expert consultants; and 3) conduct an implementation feasibility trial by leveraging implementation science frameworks (e.g., CFIR) to optimize intervention delivery, assess the acceptability of the adapted EBI for LSGM, and explore our capacity to collect preliminary outcomes using the RE-AIM framework. This research is in alignment with the...