High Rate of Hepatitis C Virus Reinfection Among Recently Injecting Drug Users: Results From the TraP Hep C Program-A Prospective Nationwide, Population-Based Study

Background. The Treatment as Prevention for Hepatitis C program started in 2016 in Iceland, offering treatment with direct-acting antivirals to hepatitis C virus (HCV)-infected individuals. Reinfections through injection drug use (IDU) can hamper elimination efforts. We determined reinfection rates of HCV among patients in the program. Methods. Clinical data were gathered prospectively. The study cohort consisted of HCV-cured patients with an estimated sustained virologic response between 1 February 2016 and 20 November 2018, with follow-up until 20 November 2019. The observation period and time until reinfection was estimated using a single random point imputation method coupled with Monte Carlo simulation. The reinfection rates were expressed as reinfections per 100 person-years (PY). Results. In total, 640 treatments of 614 patients (417 male; mean age, 44.3 years) resulted in cure, with 52 reinfections subsequently confirmed in 50 patients (37 male). Follow-up was 672.1 PY, with a median time to reinfection of 232 days. History of IDU was reported by 523 patients (84.8%) and recent IDU with 220 treatments (34.4%). Stimulants were the preferred injected drug in 85.5% of patients with a history of IDU. The reinfection rate was 7.7/100 PY. Using multivariate Cox proportional hazards models for interval-censored data, age (hazard ratio, 0.96 [95% confidence interval,.94-.99]) and recent IDU (2.91 [1.48-5.76]) were significantly associated with reinfection risk. Conclusions. The reinfection rate is high in a setting of widespread stimulant use, particularly in young people with recent IDU. Regular follow-up is important among high-risk populations to diagnose reinfections early and reduce transmission.