Abstract: Objective To investigate the impact of infection route and age on responses to antiviral therapy in patients with chronic hepatitis C. Methods 113 patients with chronic hepatitis C were treated with pegylated interferon and ribavirin. The level of serum HCV RNA was measured with real-time quantitative reverse-transcription polymerase chain reaction and HCV genotypes were determined by core-envelope 1 region nucleotide sequencing followed by phylogenic analysis. Results The rate of sustained virological response （95.0%） in 20 patients with intravenous drug use was significantly higher than that in 54 patients with iatrogenic infection （75.9%,P<0.05） and 39 with unknown infection route（69.2%,P<0.05）;the rate of sustained virological response （82.9%） in patients under 40 years old was significantly higher than that in patients older than 40 years （65.1%, P<0.05）;the patients with intravenous drug use was mainly infected with HCV genotype 3（45%） and genotype 6（50.0%）,and the proportion of HCV genotype 1b in patients with iatrogenic infection and those with unknown infection route were 51.9% and 43.6%,respectively;64.7% of patients younger than 40 and without drug use were infected by HCV genotypes non- 1（2,3-and 6-type）,while 64.3 % of patients older than 40 were infected by HCV genotype 1（P<0.05）. Conclusions The patient's age and infection route could be important factors for predicting response to antiviral therapy.

Key words: Hepatitis C, Infection route, Hepatitis C viral genotypes, Pegylated interferon