Introduction
This report describes the methods and findings 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’. The aim of the work was to assess the latest evidence on the effectiveness of select interventions — specifically, drug treatment, needle and syringe programmes (NSPs), drug consumption rooms and the combination of opioid agonist treatment (OAT) and NSPs — in the prevention of hepatitis C virus (HCV) transmission, HIV transmission, injecting risk behaviour (IRB) and injection frequency (IF) among people who inject drugs.