Hepatitis C Virus in mainland China with an emphasis on genotype and subtype distribution

Abstract

Due to the low fidelity of the RNA-dependent RNA polymerase, Hepatitis C virus (HCV) mutates quite frequently. There are seven genetically divergent genotypes (GTs) distributed in the world, each of which contains several closely related subtypes. The peer-reviewed literatures reporting the prevalence rate of HCV GTs in Chinese hospitalized patients were identified by systematic searching of three electronic databases, and the prevalence rates were pooled through 137 qualified studies. The significant difference between HCV GT and HCV viral load and severity of hepatitis were analyzed under Chi-squared or Fisher's exact test. Data from epidemiological studies on hospitalized patients demonstrated that HCV GTs 1-6 have been found in China, of which 1b (62.78%(95% CI: 59.54-66.02%)) and 2a (17.39% (95% CI: 15.67-19.11%)) are the two predominant subtypes. HCV GTs and subtypes exhibits significant regional divergence. In North, Northwest, Northeast, East (except Jiangxi province) and Central China (except Hunan province), HCV-1b, 2a remain the two predominant subtypes; South China shows the most abundant genetic diversity that 14 subtypes were found, and HCV-3 in the Southwest China remains higher prevalent subtype than the other regions. In addition, co-infection in Liaoning province of Northeast China is the most diverse with 10 co-infection types, and Tibet has the highest rate of co-infection. The associations between HCV GTs and patients group, severity of illness and antiviral treatment efficacy were also discussed in this review.

Keywords: Antiviral treatment efficacy; Co-infection; Distribution; HCV genotype; Population demographics; Subtypes.

Fig. 1

Flow diagram of summary of search strategy

Fig. 2

Map of HCV GT/subtypes distribution in various regions of mainland China. The seven colors in the map represent Chinese seven divisional regions; the vertical bars indicate the top five subtypes in the different region of mainland China; the horizontal bars in the lower left corner indicates the HCV genotypes and subtypes found in mainland China. The colored arrows marked in the below of genotype distribution in South and Southwest China indicates the proportion trend change of HCV genotypes with time: subtypes 1b and 2a decreased with red arrow, and genotype 3 increased with green arrow