Direct antiviral therapy (standard of care) administered to chronic hepatitis C-infected patients, in two hepatology clinics, who had used intravenous drugs in the past 6 months of signing informed consent (IC). This cohort was compared to concurrently treated chronic hepatitis C patients who were not intravenous drug users, who signed IC in these same clinics. Follow-up expected two years after cure and relapse rates recorded.

Primary end point was SVR rate and secondary end points included reinfection rates in follow-up period.

Chronically HCV-infected participants were recruited and treated at two liver referral clinics in Georgia, but had been referred from opioid substitution therapy clinics, primary care and GI clinics, neighboring hospitals, and correctional centers. Once consented, a nurse navigator was assigned to each participant was responsible for all subjects' appointments, and med supplies. Drug testing was mandated at specified intervals. Patients with recent injection drug use (within 6 months) were assigned to the PWID (people who inject drugs) arm, and those who hadn't injected within 6 months, but agreed to be in the study and signed consents, were assigned to the non-PWID arm. Both groups were treated with velpatasvir (100 mg) and sofosbuvir (400 mg) once daily for 12 weeks (brand or branded generic). Adherence was assessed by pill counts. Mandatory treatment visits were scheduled for baseline, 4 and 12 weeks (+/- 2 weeks) and follow-up (FU) week 12 (+ 4 months). Long-term FU was flexible and could be virtual, but was mandated once yearly with HCV RNA testing.

Inclusion Criteria:

• Chronic HCV infection and PWID arm: use of intravenous drug use at least once in preceding six months. In Non-PWID arm: no use of intravenous drug use at least once in preceding six months.

Exclusion Criteria:

• Co-infection with chronic hepatitis B; Decompensated cirrhosis current or by history; inability to sign informed consent; unwilling to take therapy or unable to obtain therapy