Investigating rates and risk factors for hepatitis C virus reinfection in people receiving antiviral treatment in England.

England has committed to the World Health Organization target to eliminate hepatitis C virus (HCV) as a public threat by the year 2030. Given successful treatments for HCV in recent years, it is unclear whether HCV reinfection will impact England's ability to achieve HCV elimination. We aimed to estimate the HCV reinfection rate among a cohort of patients receiving antiviral treatment using available surveillance data. Linkage between a treatment dataset from 2015 to 2019 and an HCV RNA testing dataset were used to identify people who experienced reinfection using three criteria. A Cox proportional hazards model was used to determine risk factors associated with HCV reinfection among a cohort who received treatment and had follow-up HCV RNA testing. The reinfection rate among those receiving HCV treatment was 7.91 per 100 person-years (PYs, 95% confidence interval (CI) 7.37-8.49) and highest among current injecting drug users (22.55 per 100 PYs, 95% CI 19.98-25.46) and people who had been in prison (20.42 per 100 PYs, 95% CI 17.21-24.24). In the adjusted model, women had a significantly reduced risk of reinfection. Being of younger age, current injecting drug users, and receipt of first treatment in prison were each significantly associated with increased risk of reinfection. Two-fifths of those with reinfection (43%, n = 329/767) were linked to treatment after reinfection, and of those starting treatment, three quarters (75%, n = 222/296) achieved a sustained virologic response. Guidance for testing groups at risk of reinfection and harm reduction strategies to minimize transmission should be implemented if England is to achieve HCV elimination targets.