IFNA1 and infection: Genotype 1 is the most prevalent in the world and in Brazil (HCV-GT1a and HCV-GT1b, respectively) and is associated with more severe liver disease and a more aggressive course of infection, in addition to presenting a worse sustained virological response (SVR) to conventional treatment with peg-interferon (Peg-IFN) and ribavirin (RBV) or Peg-IFN/RBV (35–45%) [6,7].