Trickey A, et al. - In this modelling study, researchers projected the global, regional, and country-level contribution of injection drug use to the risk of hepatitis C virus (HCV) epidemics. To replicate country-level HCV epidemics in people who inject drugs and the population in general, a dynamic deterministic HCV transmission model was created. The model was made up of 88 countries and predicted that 0.23% of the global population in 2017 were injection drug users and 8% of prevalent HCV infections were among those currently injecting drugs. Unsafe injection practices among these people make a substantial contribution to the global incident of HCV infections. A marked effect on the incidence of HCV at the country level could result from any intervention that can reduce the transmission of HCV among people who inject drugs.