We administered alfacalcidol as vitamin D source in combination with PEG-IFN/ ribavirin therapy for elderly patients with chronic hepatitis C infection of high-viral-load HCV genotype 1b, and compared therapeutic outcome and safety with patients matched for age, gender and IL28B genotype, who received PEG-IFN/ ribavirin alone without alfacalcidol. This evidence concerns the gene IFNL3 and chronic hepatitis C virus infection.