The purpose of this research proposal is to investigate the impact of HCV treatment of HIV/HCV coinfected and HCV monoinfected incarcerated persons on HCV elimination. Of particular importance is understanding why safe, curative treatment has not reached most of the incarcerated HCV infected persons who largely are unaware of their infected status. The high cost of HCV treatment is a major reason for this knowledge gap. High treatment prices provide an enormous incentive for states to shroud the epidemiology and treatment of HCV. Subtle and even overt barriers to testing and treatment are sustained to diminish the net economic impact. Accordingly, relative to HIV, little HCV testing and treatment has occurred in correctional facilities in the U.S. Louisiana removed the cost of medications as a factor by establishing an alternative payment strategy with the goal of treating 80% of HCV infected persons by 2024 in their HCV Elimination Program. Under the program, Louisiana pays the same amount for HCV medications no matter how many persons are treated. Thus, now for the first time, we have the opportunity to investigate rigorously the burden of HCV in the correctional system in a U.S. state, the dynamics of incarceration, and the resulting prevalence of infection. We want to apply this new knowledge to estimating the potential impact of treatment on community HCV transmission and mortality. In the next cycle, we propose research to achieve these aims: (1) To characterize the dynamics of HCV infection in the correctional system among HIV/HCV coinfected and HCV monoinfected incarcerated persons; (2) To assess treatment impact as the trajectory of decline in HCV viremia among HCV antibody positive incarcerated persons and whether this trajectory differs between those with and without HIV; (3) To disentangle the impact of the correctional HCV treatment program on HCV viremic decline, and to assess the impact of scale-up of correctional treatment programs on HCV incidence and mortality in Louisiana and elsewhere.