Hepatitis B virus genotypes: epidemiological and clinical relevance in Asia

Abstract

Hepatitis B virus (HBV) is characterized by a high genetic heterogeneity since it replicates via a reverse transcriptase that lacks proofreading ability. Up to now, ten genotypes (A-J) have been described, with genotype A and D being ubiquitous but most prevalent in Europe and Africa, genotype B and C being confined to Asia and Oceania. Infections with other genotypes such as E, F, G and H are also occasionally observed in Asia. Genotype I is rare and can be found in Laos, Vietnam, India and China, whereas genotype J has been described in Japan and Ryukyu. Novel variants generated by recombination and co-infection with other genotypes have gradually gotten worldwide attention and may be correlated with certain clinical features. There are substantial differences in HBV infection regarding prevalence, clinical manifestation, disease progression and response to antiviral therapy. Due to the complex interplay among viral, host and environmental factors, the relationship between HBV genotypes and clinical profiles remains incompletely revealed. In general, genotype A is associated with better response to interferon therapy; genotype C, and to lesser extent B, usually represent a risk factor for perinatal infection and are associated with advanced liver diseases such as cirrhosis and hepatocellular carcinoma; genotype D may be linked with poor response to interferon therapy. Future studies with better design and larger sample size are warranted to further clarify the controversial issues and guide the day-to-day clinical practice.

Recapitulation of treatment response patterns in a novel humanized mouse model for chronic hepatitis B virus infection

“…Persistent infection with hepatitis B virus (HBV) is a global health problem afflicting approximately 400 million individuals worldwide, with Asia being disproportionally affected with over 130 million chronic cases (Tian and Jia, 2016). Chronic HBV carriers are at risk of developing fibrosis, cirrhosis or hepatocellular carcinoma (Trepo et al, 2014).…”

Baseline Characteristics and Treatment Patterns of the Patients Recruited to the China Registry of Hepatitis B

“…1 The 2017 World Health Organization (WHO) Global Hepatitis Report estimates that 257 million persons, or 3.5% of the population, are chronically infected by HBV, 2 with the highest hepatitis B surface antigen (HBsAg) prevalence (6.2%) being in the Western Pacific region. [3][4][5] Chronic HBV infection is asso-ciated with a considerable burden of liver morbidity and mortality, and can lead to cirrhosis, decompensation and hepatocellular carcinoma (HCC). 6 In China, with high coverage of HBV vaccination in infants, the estimated prevalence of HBsAg declined to 6.1% in the general population.…”

Interference of Apoptosis by Hepatitis B Virus

“…In the USA, HBV infection is most common among Asians [ 7 ]. Up to now, ten genotypes (A–J) of HBV have been identified [ 8 ]. Genotypes A and D are ubiquitous but prevalent in Europe and Africa, while genotypes B and C are confined in Asia and Oceania.…”

“…HBV integration into this site leads to the overexpression of c-Myc and PVT1 , and consequent HCC progression [ 17 ]. Aside from the HBV B2 genotype, the HBV C genotype also accounts for a large number of clinical HCC cases [ 8 ].…”