Infrequent reinfection after successful treatment for hepatitis C virus infection in injection drug users.

We followed-up 18 injection drug users for a mean of 33.8 months (range, 4-55 months) after successful treatment for hepatitis C virus (HCV) infection. Fifteen (83%) of the patients remained HCV RNA-negative, 1 patient was not tested, and 2 patients had test results positive for HCV RNA. The estimated rate of reinfection as a result of injection drug use was 0-4.1 cases per 100 person-years (cumulative incidence, 0%-12.6% at 48 months after completion of treatment). Of 50 patients originally treated, 15 (30%) were HCV RNA-negative 3 years later.