Hepatitis C transmission and progression among people who have injected drugs in Singapore: Modelling treatment for eradication

BackgroundHepatitis C virus (HCV) disproportionally affects people who inject drugs (PWID), posing a public health challenge. The high incarceration rate among PWID provides an opportunity for screening and treating individuals with chronic HCV infection in correctional facilities. MethodsWe developed a deterministic age-structured model to characterise the HCV transmission among PWID both inside and outside prison settings. We proposed diverse treatment strategies, targeting varying proportions of current and former PWID. Utilising demographical and epidemiological data on PWID in Singapore, we assessed the impacts of these strategies on preventing HCV infections and HCV-related complications. ResultsThe overall HCV prevalence among PWID is estimated at 31.3% (95% CrI: 30.7% - 32.1%) without intervention. Treating all detained ex-PWID in the early stages of chronic HCV infection could prevent 25,878 infections (95% CrI: 20,485 - 31,575) over 50 years, comparable to treating 15% of current PWID in the community. However, treating 15% of former PWID in the community would have a greater impact in reducing advanced HCV cases and HCV-related deaths. A combined approach covering 12% of current PWID, all detained ex-PWID, and 13% of former PWID in the community would nearly eliminate HCV infections among PWID, reducing infections to 0.3% (95% CrI: 0.25% - 0.45%) of ever-PWID 30 years after treatment initiation. InterpretationEliminating HCV infections among PWID is achievable but costly, particularly when targeting all PWID regardless of incarceration. Treating detained PWID offers a more feasible and cost-effective alternative. Policymakers should strike a balance between budget constraints and treatment effectiveness to optimise public health outcomes.