A national PrEP program could provide direct assistance to purchase health insurance for individuals with low incomes who are not eligible for other insurance due to gaps in Medicaid coverage and ineligibility for Affordable Care Act marketplace subsidies. However, the potential population benefit of a comprehensive national PrEP program remains unclear. This project will use an existing sexual-network model of HIV/STI transmission dynamics among men who have sex men (MSM) to investigate the optimal strategy for a national PrEP program targeted to MSM with indications for PrEP and varying needs for financial assistance. This project aims to develop models for three metropolitan statistical areas (MSAs) with different profiles of HIV burden and healthcare coverage: Atlanta, Washington, D.C., and New York City.