Some studies have evaluated the effect of reduced dose peg-IFN α-2b (lowered from 1.5 mg/kg body weight to 0.5 mg/kg body weight) plus ribavirin on chronic hepatitis C and found that low-dose peg-IFN α-2b in combination with ribavirin is as effective as standard high-dose peg-IFN α-2b plus ribavirin on chronic hepatitis C [11–14]. This evidence concerns the gene IFNA1 and chronic hepatitis C virus infection.