An international perspective on using opioid substitution treatment to improve hepatitis C prevention and care for people who inject drugs: Structural barriers and public health potential.

People who inject drugs (PWID) are central to the hepatitis C virus (HCV) epidemic. Opioid substitution treatment (OST) of opioid dependence has the potential to play a significant role in the public health response to HCV by serving as an HCV prevention intervention, by treating non-injection opioid dependent people who might otherwise transition to non-sterile drug injection, and by serving as a platform to engage HCV infected PWID in the HCV care continuum and link them to HCV treatment. This paper examines programmatic, structural and policy considerations for using OST as a platform to improve the HCV prevention and care continuum in 3 countries-the United States, Estonia and Viet Nam. In each country a range of interconnected factors affects the use OST as a component of HCV control. These factors include (1) that OST is not yet provided on the scale needed to adequately address illicit opioid dependence, (2) inconsistent use of OST as a platform for HCV services, (3) high costs of HCV treatment and health insurance policies that affect access to both OST and HCV treatment, and (4) the stigmatization of drug use. We see the following as important for controlling HCV transmission among PWID: (1) maintaining current HIV prevention efforts, (2) expanding efforts to reduce the stigmatization of drug use, (3) expanding use of OST as part of a coordinated public health approach to opioid dependence, HIV prevention, and HCV control efforts, (4) reductions in HCV treatment costs and expanded health system coverage to allow population level HCV treatment as prevention and OST as needed. The global expansion of OST and use of OST as a platform for HCV services should be feasible next steps in the public health response to the HCV epidemic, and is likely to be critical to efforts to eliminate or eradicate HCV.