Molecular characterization of hepatitis C virus genotype 6 subtypes in Thai blood donors

Genetic history of hepatitis C virus genotype 6 in Taiwan

Unlike hepatitis C virus (HCV) genotype (GT) 6, which is widely circulated in Southeast Asia and South China, GT 6 was not reported in Taiwan until 2006. GT 1b and 2a, also known as global HCV subtypes, have been reported as major GTs circulating in Taiwan. Because of improvement in genotyping kits and sequencing techniques for the subtyping of HCV, an increasing number of GT 6 subtypes have been reported, especially subtype 6a among intravenous drug users with human immunodeficiency virus infection after an outbreak since 2003. Thus, HCV GT 6 infection is regarded to be closely associated with injection drug use. However, recently, we found an unexpectedly high GT 6 prevalence in the general population in Tainan, southern Taiwan. Most of these GT 6 samples belonged to a putative novel subtype closely related to 6g and 6w instead of 6a. Phylogenetic analyses indicated that this putative 6g-related novel subtype and 6w could be indigenous in southern Taiwan for centuries. Southern Taiwan could be the origin of HCV subtype 6w. This finding might change the perspective of HCV epidemiology in Taiwan.

Partial nonstructural 3 region analysis of hepatitis C virus genotype 3a

BACKGROUND

The hepatitis C virus (HCV) is a major cause of illness around the world. HCV genotype 3a is the most prevalent genotype in Thailand. Direct-acting antiviral (DAA) drugs are available for treatment, and these drugs target the NS3, NS5A, and NS5b proteins of HCV. However, HCV variants that are resistant to NS3 protease inhibitors have been found during treatment. This resistance can be naturally occurring or in response to treatment. The purpose of this study is to analyze the codon positions of the main mutation of the partial NS3 gene region of HCV genotype 3a.

METHODS

In order to detect mutations and confirm the genotype of HCV genotype 3a, the nucleotide sequencing and amino acid portion of NS3 were analyzed.

RESULTS

Twenty-six samples were successfully sequenced and clustered within two sub-clades defined as 3a-1 and 3a-2. Through amino acid mutation analysis, the variations were detected at codon positions 122 (3.8%), 132 (84.6%), 168 (100%), 170 (92.3%), 174 (100%), and 175 (100%).

CONCLUSIONS

In conclusion, mutations at positions 168, 170, 174, and 175 of the NS3 region are common within the HCV genotype 3a. This information should be useful in the development of effective anti-viral drugs that can successfully treat HCV infection.

Treatment Response and Drug Resistance Profiling of Genotype 6 of Hepatitis C Virus in HCV/HIV Co-Infected Patients: A Pilot Study from INDIA

Hepatitis C Virus (HCV) genotype (GT) 6 demonstrates maximum genomic diversity out of all the known genotypes of HCV, attributable to its inherent intra-genotype and inter-genotype recombination property. This is the most common genotype seen in HCV/HIV co-infected cases. HIV/HCV co-infection is linked with increased genetic diversity in HCV structural genes. The detailed information on the distribution of HCV GT6, its subtypes, and resistance to currently available antiviral drugs is limited in the Indian subcontinent. Therefore, in this single-center retrospective cross-sectional study, we aimed to map the occurrence of HCV GT6, its subtypes and resistance-associated substitution (RAS), and its correlation with antiviral treatment response in HCV-infected patients. From a cohort of 2052 HCV-infected patients, the overall prevalence of GT6 was 2.5% (n = 53), with a maximum of 81.1% (n = 43) seen in HCV/HIV co-infected patients. Nine different subtypes, 6a, 6b, 6f, 6i, 6n, 6u, 6v, 6w, and 6xa, were detected in the Indian population for the first time, with a predominance of 6xa (41.5%), a rare subtype, followed by 6n (39.6%). The phylogenetic analysis by the neighbor-joining method revealed three prominent viral clades, 6v, 6n, and 6xa–6u. The baseline (before treatment initiation) plasma samples of all GT6-infected patients were retrieved from −80 °C and a part of the NS5a and NS5b region of the viral genome was analyzed for the presence of RAS. No RASs were seen in the NS5b region, while in two patients (3.7%) RASs were seen at baseline in the NS5a region of the virus. Sustained viral response (SVR) was attained in 81% (n = 43) of patients. No difference in GT6 subtype distribution or occurrence of RAS was seen between mono-infected HCV and HIV/HCV co-infected cases. Our study revealed that RAS at baseline did not influence the attainment of SVR and the currently available antiviral therapy is effective against GT6 mono-infected and HIV/HCV co-infected patients.

Evaluation of cost-effectiveness of peginterferon plus ribavirin for chronic hepatitis C treatment and direct-acting antiviral agents among HIV-infected patients in the prison and community settings

BACKGROUND

In Taiwan, the majority of chronic hepatitis C carriers with HIV co-infection are intravenous drug users and inmates in correctional facilities. Peginterferon and ribavirin (PegIFN/RBV) have been the standard-of-care for chronic hepatitis C virus (HCV) infection more than decades. We evaluated the estimated cost-effectiveness of PegIFN/RBV from the National Health Insurance Research Database, covering the population of Taiwan from 1998 to 2013.

MATERIALS AND METHODS

This is an observational study, and study during was 2010-2016 and a total of 239 patients were treated with PegIFN/RBV. Of them, 156 patients were treated in the correctional facilities of Taipei, Taoyuan, Taichung and Taitung prisons, and 83 patients were treated in communities. The cost-effectiveness was analyzed in regimens of PegIFN/RBV and direct-acting antiviral agents.

RESULTS

By multivariate analysis, the patients completed PegIFN/RBV in prison (adjusted odds ratio [aOR]: 4.56, 95% confidence interval [CI]: 1.58-13.12, p = 0.005), HCV RNA level <800,000 IU/mL (aOR: 4.0, 95% CI: 1.27-12.66, p = 0.02) at baseline, and the presence of early virologic response (EVR) (aOR: 7.67, 95% CI: 1.89-31.06, p = 0.004) were independent predictors for sustained virologic response (SVR). For the subgroups of prisoners, HIV-infected prisoners and HIV-infected patients in communities, the SVR rate was 73.8%, 72.0% and 36.8%, and the average medical-care cost was US$7,701, $7,893, and $15,443 per SVR achieved, respectively. Also, the estimated medical-care cost for genotype 6 was US$9211.

CONCLUSIONS

Chronic HCV/HIV co-infected patients with genotype 1 and 6 in the community setting could benefit from DAAs in Taiwan.

Characterization of partial NS5B region among hepatitis C virus genotype 6 subtypes isolated from Thai blood donors

The hepatitis C virus (HCV) is an important cause of liver dysfunction which continues to spread in Thailand, particularly as genotype 6. The NS5B gene fragment is particularly variable and thus provides a valuable tracker for its spread. Therefore, the purpose of this study was to characterize the HCV genotype 6 based on partial NS5B region using Thai blood donor samples. Twenty-nine samples were genotyped as HCV 6 by nested PCR, nucleotide sequencing and amino acid sequence analysis. Amplified products were identified as HCV genotypes 6f, 6c, 6n, and 6i. There were amino acid variations of 4-18 residues in subtypes 6f, 6c, and 6n whereas subtype 6i was conserved when compared with their referent strains. In subtypes 6f, 6c, 6n, and 6i, the amino acid mutations at positions 244, 309, and 310 which are associated with HCV resistance were present. In summary, the sequences and phylogenetic analysis of NS5B of HCV used in our study yielded the genotypes 6f, 6c, 6n, and 6i. This finding indicates diversity of amino acids in NS5B of HCV. Characterizing the partial NS5B region among hepatitis C virus genotype 6 subtypes may predict efficacious anti-HCV therapy. J. Med. Virol. 88:1785-1790, 2016. © 2016 Wiley Periodicals, Inc.