Natural history of HCV, screening, and treatment among PWID a, a PWID enter the model uninfected with HCV and HIV and may follow different health state trajectories as shown in the flow diagram.

At any point, PWID may acquire HIV or exit the model due to background mortality or HIV-related mortality among HIV-infected PWID. Dashed lines depict the health states where PWID can be screened for HCV. Arrowed lines depict annual transition probabilities with the exception of HCV-antibody screening (which takes place every two years).