Introduction
This report describes the methods and findings of a systematic review of mathematical modelling studies of the population-level impact of opioid agonist treatment (OAT) and needle and syringe programmes (NSPs) on hepatitis C virus (HCV) transmission among people who inject drugs (PWID). This review is one component of a series of systematic reviews of the literature undertaken to update the European Centre for Disease Prevention and Control (ECDC) and European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) 2011 joint guidance on ‘Prevention and control of infectious diseases among people who inject drugs’.