Molecular epidemiology of hepatitis B virus.
Although safe and effective vaccines for hepatitis B virus (HBV) have been available for nearly three decades, this virus kills at least 600,000 people annually worldwide and remains the leading global cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Because the HBV reverse transcriptase lacks a proofreading function, many HBV genotypes, subgenotypes, mutants, and recombinants exist. At least 10 HBV genotypes (HBV-A through J) with distinct geographic distributions have been identified; by definition, their complete genomic sequences diverge by more than 8%. HBV genotype is increasingly becoming recognized as an important factor in the progression and clinical outcome of HBV-induced disease. Infections by HBV-C or -D are significantly more likely to lead to cirrhosis and hepatocellular carcinoma than are infections by HBV-A or -B. Additionally, the hepatitis B e antigen seroconversion response to standard or pegylated interferon is more favorable in patients with HBV-A or -B than in those with HBV-C or -D. However, therapeutic responses to nucleos(t)ide analogues are generally comparable among HBV genotypes. In conclusion, genotyping of HBV is useful in identifying chronic hepatitis B patients who are at increased risk of disease progression, thereby enabling physicians to optimize antiviral therapy for these patients.
Department of Internal Medicine, Graduate Institute of Clinical Medicine, Hepatitis Research Center, and Department of Medical Research, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan. kaojh@ntu.edu.tw
Jia-Horng
JH
Kao
D000998:Antiviral Agents / Q000627:therapeutic use; D024882:Drug Resistance, Viral / Q000235:genetics; D005838:Genotype; D006509:Hepatitis B / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D006515:Hepatitis B virus / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity; D006801:Humans; D017720:Molecular Epidemiology; D010641:Phenotype; D011379:Prognosis
D000998:Antiviral Agents