HCV reinfection highest among people with ongoing injecting drug use

Reinfection with hepatitis C virus (HCV) is low among people receiving opioid agonist therapy (OAT) but appears to be at its peak during the first 24 weeks following treatment completion and among those with ongoing injecting drug use and needle‒syringe sharing, a study has found.

A team of investigators performed a 3-year, long-term, extension analysis of participants enrolled in the Hepatitis C Patients on Opioid Substitution Therapy Antiviral Response study at 55 clinical trial sites in 13 countries. Patients were at least 18 years of age and had chronic HCV infection with genotypes 1, 4, or 6 receiving stable OAT.

The investigators then assessed serum samples for HCV infection and performed urine drug screening.

A total of 296 participants received treatment, of whom 286 could be evaluated for reinfection and 199 were enrolled in the long-term extension study. HCV infection rate was 1.7 per 100 person-years (95 percent confidence interval [CI], 0.8‒3.0).

Reinfection rate was higher among people with recent injecting drug use (1.9 per 100 person-years, 95 percent CI, 0.5‒4.8). Of the participants, 59 percent reported ongoing drug use and 21 percent injecting drug use at the 6-month follow-up visit. This remained stable during 3 years of follow-up.

“Participants were required to be 80-percent adherent to OAT at baseline and may represent a population with higher stability and lower risk for HCV reinfection,” the investigators noted.

“Rate of reinfection may be underestimated because all participants did not continue in the long-term extension study; whether participants who discontinued were at higher risk for reinfection is unknown,” they added.