IFNA1 and chronic hepatitis C virus infection: It also has been found that 135 μg peg-IFN α-2a weekly combined with RBV dosed daily according to body weight was sufficient for treatment of genotype 2 and 3 chronic hepatitis C [19], and 135 μg peg-IFN α-2a weekly monotherapy also effective in genotype 1 patients with cirrhosis [20].