We present a case study of the effects of health policies on the implementation and potential outcomes of a public health intervention, using the DRIVE project, that aims to 'end' the HIV epidemic among people who inject drugs in Haiphong, Vietnam. DRIVE's success depends on two policy transitions: (1) integration of donor-funded HIV outpatient clinics into public health clinics and expansion of social health insurance; (2) implementation of a "Renovation Plan" for substance use treatment. Interviews and focus group discussions with key informants and review of policy documents and clinic data reveal that both policy transitions are underway but face challenges. DRIVE promises to show how evolving policy affects health interventions and how advocacy based on project data can improve policy. Broad lessons include the importance of clear and consistent policies, vigorous enforcement, and adequate funding of promulgated policies.
Keywords: HIV treatment; People who inject drugs; Substance use treatment; Vietnam.