Objective      To determine the optimal treatment duration for the patients infected with hepatitis C virus genotype 3 (HCV 3) by pegylated interferon α (PEG-IFN-α) combined with ribavirin (RBV).       Methods      Clinical data of the patients with HCV genotype 3 infection who were treated with PEG-IFN-α plus RBV in our institute from January 2006 to December 2014 were comprehensively collected as possible as we could. According to the course of treatment

gene subtype

the cohort was divided into subgroups

and the virological responses and adverse reactions were compared among the subgroups.       Results      There were 150 patients enrolled in the study. The rapid virological response (RVR) and sustained virological response (SVR) were 78.52% and 90.67%

respectively in total. Among the 60 patients with HCV 3a

there were no differences in the RVR and SVR ratios among the shorten

standard and extending treatment duration groups (P0.05). In the 90 patients with HCV 3b

the RVR ratios were 7/14(50.00%)

51/62(82.26%) and 7/8(87.50%)

while the of SVR ratios were 8/15(53.33%)

63/67(94.03%) and 8/8(100.00%)

respectively for the shorten

standard and extending treatment duration groups

both with those of shorten treatment duration group significantly lower than the other groups (Chi square=7.31

P0.05; Chi square=20.14

P0.01). No obvious difference was seen in the 2 ratios between the standard and extending duration groups. In the analysis of influencing factors

shorten duration of treatment was independent unfavorable factor for acquired SVR (P0.01

OR=11.18

95%CI: 3.79～32.92）. Moreover

extending treatment duration increased the incidence of adverse reactions.       Conclusion      Sufficient dose of PEG-IFN-α plus RBV therapy for 24 weeks is still the optimal treatment for the patients with HCV genotype 3 infection. Shorten duration will reduce the efficiency

especially for the patients with HCV 3b. Extending duration seems not significantly improve the outcome

but increases the adverse effects such as bone marrow suppression.