ABSTRACT The overarching goal of this research is to develop and test an innovative strategy to improve linkage to and retention in hepatitis C virus (HCV) treatment among individuals recently released from jail. Dr. Matthew Akiyama is proposing a K99/R00 career development and research plan which will prepare him to develop interventions to improve linkage to and retention in HCV care among individuals with criminal justice system involvement. HCV is the leading cause of cirrhosis and hepatocellular carcinoma in the United States and, as of 2007, superseded HIV as a cause of death. A strong interrelationship with substance use disorders has led to epidemic proportions of HCV in correctional settings, with a prevalence of 17.4% compared with a national HCV prevalence of only 1.3%. Care coordination programs improve linkage to care among HIV+ individuals leaving correctional settings, yet no prospective studies have evaluated the strategy of care coordination for HCV+ individuals leaving correctional settings. In addition, while peers have been used in diverse settings to address barriers to medical care and are effective at increasing health knowledge, reducing risk behaviors, and facilitating linkage to health care, peer interventions have not been studied for HCV+ individuals leaving correctional settings. Dr. Akiyama has been a key contributor to the development of a care coordination intervention for improving linkage to HCV treatment that is currently underway in the New York City jail system. This proposal builds on this experience and extends it in several important ways. The goal of the mentored (K99) phase of this proposal is to provide Dr. Akiyama with sufficient training in four key skills: 1) advanced qualitative/mixed methods research, 2) developing behavioral interventions, 3) design and conduct of randomized controlled trials in correctional settings, and 4) statistical analysis of longitudinal and clustered data specific to criminal justice populations. During the mentored (K99) phase of the award we will achieve the following specific aims: 1) To identify barriers to and facilitators of linkage to care in an existing HCV care coordination program and 2) To use the barriers and facilitators identified in Aim 1 to design an enhanced, tailored, care coordination intervention with peers as a central component. In the independent R00 phase of the award, we will 3) test the feasibility and effectiveness of the peer- enhanced, tailored, care coordination intervention using a randomized design. We hypothesize that the tailored intervention, enhanced by peers, will lead to greater rates of linkage to HCV treatment, treatment initiation, treatment completion, sustained virologic response, and lower rates of HCV risk behavior. Completion of the proposed pilot trial during the R00 phase along with intensive mentorship during the K99 phase will prepare Dr. Akiyama to test the peer-enhanced care coordination intervention in a multisite randomized controlled trial in a future R01. The proposed K99/R00 award will provide training, mentorship, and research experience that will serve as the foundation for Dr. Akiyama's career as an independently funded clinical investigator dedicated to improving health outcomes for HCV+ individuals with criminal justice system involvement.