To coincide with World Hepatitis Day, the Lancet features a systematic review which attempts to estimate the national, regional, and global prevalence and population size for hepatitis C virus (HCV) and hepatitis B virus (HBV) in injecting drug users (IDUs). The authors estimate that around 10 million (range 6.0-15.2) IDUs are thought to have been exposed to HCV, while 1.2 million are hepatitis B surface antigen (HBsAg) positive. Obvious geographical differences with respect to prevalence are also identified by the authors. Eastern Europe, east Asia, and southeast Asia are estimated to have the largest populations of IDUs infected with viral hepatitis. The authors acknowledge that variation in the coverage and quality of existing research creates uncertainty around the estimates provided. They conclude, “Improved and more complete data and reporting are needed to estimate the scale of the issue, which will inform efforts to prevent and treat HCV and HBV in IDUs.”

A related Comment article discusses the paper, with the authors noting that it “provides us with a first step and powerful data to draw attention to the problem of viral hepatitis in people who use drugs. The next step is to challenge governments to act, and hold them accountable for implementation of rights-respecting and evidence-based programmes.”

A second Comment article calls for action to improve control of the disease through interventions such as vaccination and use of antiviral drugs. The authors write, “Control of viral hepatitis receives only a fraction of the attention and resources that are dedicated to other major public health threats with similar or lesser morbidity and mortality. Hence immediate action is necessary to raise awareness, build collaborations to implement interventions that are appropriate for epidemiological patterns, and motivate policy makers to support better systems of prevention, care, and treatment of viral hepatitis.”