Combating Related Epidemics in HCV through Simplified Testing and Treatment (CREST) - PROJECT SUMMARY/ABSTRACT The opioid epidemic is a primary driver of new hepatitis C virus (HCV) infections, especially among younger (<40 years) people who inject drugs (PWID), including new outbreaks. PWID are also at risk of human immunodeficiency virus (HIV) infection and therefore a key population for engagement in preventative interventions, including pre-exposure prophylaxis (PrEP). The United States has proposed integrated models of care to address these syndemic conditions. In PWID, HCV transmission mostly occurs in the first two years after drug injection initation, while for HIV it occurs after 6-8 years, providing support for new HCV infections outpacing new HIV infections in this key population. Jumpstarting and integrating diagnosis, treatment, and prevention for HIV and viral hepatitis in the US is critical to address these overlapping epidemics. The magnitude of HCV infection in the US and our inability to meet global (World Health Organizatioin, WHO) and US (Center for Disease Control and Prevention, CDC) goals requires innovations in how care for HCV and HIV is delivered, which will be addressed in this application. Bringing together an international consortium with broad and relevant expertise, we propose a clinical trial to demonstrate the feasibility, acceptability, and clinical effectiveness of a single-visit POC test & treat integrated care model approach addressing roadblocks in the HCV care continuum and integration of HIV prevention and treatment linkage services. The results of this landmark trial could deliver a paradigm shift in the approach to HCV care in the US and inform strategies for HCV elimination globally. The overall objective of the proposed research is to directly address the 3 key priorities of the US National HCV Elimination Program, which include: (1) expansion of POC diagnostic testing; (2) broad access to curative HCV medications; and (3) efforts to engage, inform, identify, and treat people with HCV infection. With availability of POC tests for HCV, HIV, and HBV infections, novel integrated care models, as proposed in this application, can be developed and tested for overcoming barriers to prevention and treatment of HIV and HCV. Our long-term goal is to contribute to the elimination of HCV infection in the US. To achieve this goal we propose the following specific aims: 1) Evaluate the effectiveness of a single-visit point-of-care test & treat bundle on outcomes relating to HCV and HIV among key populations, including people with or at risk for HIV, 2) To assess the acceptability, barriers, and facilitators of an integrated POC HCV test & treat care model for participants, healthcare providers, and testing operators, and 3) Evaluate the cost-effectiveness, affordability, and long-term epidemiological impact of a scaled-up single-visit test & treat care model among key populations, including people with or at risk for HIV.