Factors that have an effect on the rate of sustained virological response (SVR) in chronic hepatitis C (CHC) patients include: genotype of hepatitis C virus (HCV); level of HCV RNA replication and rate of its reduction in the course of treatment; original hepatic fibrosis level; genotype of Interleukin-28B (especially for Genotype 1 HCV – G1); daily ribavirin (RBV) dose. This evidence concerns the gene IFNL3 and cryohydrocytosis.