Hepatitis C reinfection following successful direct-acting antiviral therapy among patients attending a multidisciplinary treatment centre for people who use drugs in Zurich, Switzerland.

Abstract

On-going risk-exposure followed by reinfection may jeopardize hepatitis C elimination efforts among people who use drugs. We estimated the HCV reinfection incidence in patients who successfully completed HCV therapy and attended a low-threshold access centre for comprehensive addiction medicine. Retrospective chart review was undertaken, in a convenience sample of patients with opioid/cocaine use disorders who achieved sustained viral response (SVR) after direct-acting antiviral (DAA) therapy in Zurich, Switzerland between April 2015 and July 2019 (n=153). HCV reinfection incidence in patients with and without on-going drug use was calculated. 79% of the patients were in opioid agonist treatment, and 19% were being managed for other medical or psychiatric conditions. 58% used drugs after SVR, of whom 49% injected. The follow-up period totalled 346 (median 2.1) person-years (py). Overall HCV reinfection incidence was 1.2 (CI-95: 0.3 to 3.0) per 100 py and 1.6 (0.2 to 5.8) in patients with drug use after SVR. The risk of HCV reinfection after DAA therapy in persons who use drugs can be low if, after SVR, patients remain in care in a well developed comprehensive harm reduction setting.