IFNA1 and chronic hepatitis C virus infection: Nevertheless, there is limited data on efficacy of low-dose peg-IFN α-2a (90 μg/week) plus ribavirin on chronic hepatitis C. In a previous study, forty-eight weeks of treatment with 90 μg/week peg-IFN α-2a is safe and produces an SVR in 35–40% of patients with chronic hepatitis C [16].