PROJECT SUMMARY The proposed K01 application will catalyze Dr. Tao’s independent career as an infectious disease epidemiologist with expertise in HIV prevention and pre-exposure prophylaxis (PrEP), qualitative interviews, respondent driven sampling (RDS), social network analysis (SNA), and mathematic modeling in addressing health disparities in access to PrEP care (Career goals). The PI and her co-primary mentor are based in the Department of Medicine at Brown University, and will also work closely with co-primary mentor and co-mentors at the School of Public Health at Brown University, at Rutgers University, and at the University of Mississippi. Together, this team of mentors and institutional environment will allow the junior PI a high chance of success in completing the research goals and becoming an NIH-funded independent investigator. African American (AA) and Hispanic/Latino (H/L) men who have sex with men (MSM) bear a disproportionate HIV disease burden in the United States (US). PrEP is highly effective in reducing HIV acquisition, but PrEP uptake among AA and H/L MSM has been slow compared to White MSM. Effective and novel interventions are needed to promote PrEP uptake in these populations to reduce HIV incidence. A peer-driven intervention (PDI) is based on RDS methodology and has been demonstrated to be a highly effective, culturally appropriate, and low-cost approach to engage hard-to-reach populations in HIV prevention. The effect of a PDI on PrEP uptake, especially among AA and H/L MSM, is unknown. In this proposed study, we will conduct 30 individual interviews (15 AA and 15 H/L MSM) to explore facilitators and barriers to PrEP uptake and determine components of an effective PDI among AA and H/L MSM (Specific Aim[SA]1). The effect of a PDI on PrEP uptake will be assessed and compared to a group of AA and H/L MSM who will be recruited by venue-based sampling (N=200, 50 AA and 50 H/L MSM in each group) (SA2). Using data from the SA2, we will perform microsimulations in the context of an agent-based model to evaluate the impact of a PDI on PrEP uptake and HIV incidence at the population level (SA3).