Wei Ju1, Song Yang1, Qi Wang1, Huichun Xing1, Yao Xie2, Wen Xie2, Jun Cheng1; 1Beijing Ditan Hospital Capital Medical University,Beijing, China; 2Beijing Ditan Hospital,Beijing, China
Determination of HCV genotype is significant for the prediction of response to anti-viral therapy and duration of treatment. This is an epidemiological study of patients infected chronically with HCV in mainland China. A total of 853 HCV RNA positive serum samples were collected from chronic HCV infected patients from 23 administrative units in mainland China during 2009.10 - 2011.6.
The serum samples were subjected to RTPCR followed by direct DNA sequencing and phylogenetic analysis of NS5B and/or CORE-E1 regions. HCV genotypes were available in 811 samples [95.1% (811/853)]. The results indicated new trends of HCV infection in mainland China. Phylogenetic analysis revealed that genotype 1, 2, 3 and 6 were detected. No genotype 4 and 5 strains were found.
The distribution of HCV subtypes was 1b, 2a, 3a, 6a, 3b, 6n, and 1a at frequencies of 73.1%, 18.5%, 3.2%, 2.5%, 1.8%, 0.5%, and 0.4%, respectively. HCV subtype 1b was the most frequent in mainland China followed by 2a. The HCV genotype distribution differed according to the patients’ region of origin and genotypes 3 and 6 represented an increasingly wide range of geographic distribution. Patients infected with HCV subtype 1b and 2a were found statistically older than those infected with 3a, 3b, 6a and 6n, respectively. Blood transfusion was the main route of transmission. IDUs and tattooing / piercing were more common among patients with genotype 3 compared with those with genotype 1.
This study is the largest report of molecular epidemiology of HCV in mainland China and demonstrates a genetic heterogeneity of HCV infection, with at least four HCV genotypes and seven subtypes. Clinical trials of direct anti-HCV agents (DAA) should consider this genetic heterogeneity.