Low incidence of reinfection with the hepatitis C virus following treatment in active drug users in Amsterdam.

BACKGROUND: More than two-thirds of hepatitis C virus (HCV) infections are associated with injecting drug use. Despite the wide availability of standard treatment with pegylated interferon and ribavirin, active drug users (DU) have limited access to HCV treatment. Physicians may be reluctant to prescribe treatment because of the presumed high risk of reinfection. However, data on reinfection in treated DU remain scarce.

METHODS: Active DU with chronic HCV infection were treated in a multidisciplinary setting. After achieving a sustained virologic response, patients were tested at 6-12-monthly intervals for HCV RNA. To distinguish between relapse and reinfection, sequence and phylogenetic analyses were performed on the NS5B region of the HCV genome. The incidence of reinfection was calculated using person-time techniques.

RESULTS: From April 2005 to March 2010, 69 active DU treated for HCV had sufficient follow-up, median 2.5 years (interquartile range, 1.6-3.7). Sustained virologic response was achieved in 42 patients (61%). During follow-up, 41 patients remained HCV RNA-negative; of these, two patients died. During treatment, five out of 41 injected drugs, which increased to 11 out of 41 after the end of treatment. One case of reinfection was observed, followed by spontaneous clearance of the virus. The overall incidence was 0.76/100 person-years (95% confidence interval 0.04-3.73). For only those individuals reporting injecting drug use, the incidence was 3.42/100 person-years (95% confidence interval 0.17-16.90).

CONCLUSION: We report a low incidence of HCV reinfection following treatment in DU participating in a multidisciplinary programme. Active drug use, including injecting, should not preclude access to treatment for HCV.