Hepatitis B Virus Infection: Epidemiology and Vaccination

Worldwide, two billion people have been infected with hepatitisB virus (HBV), 360 million have chronic infection, and 600,000die each year from HBV-related liver disease or hepatocellularcarcinoma. This comprehensive review of hepatitis B epidemiologyand vaccines focuses on definitive and influential studies andhighlights current trends, policies, and directions. HBV canbe transmitted vertically, through sexual or household contact,or by unsafe injections, but chronic infections acquired duringinfancy or childhood account for a disproportionately largeshare of worldwide morbidity and mortality. Vaccination againstHBV infection can be started at birth and provides long-termprotection against infection in more than 90% of healthy people.In the 1990s, many industrialized countries and a few less-developedcountries implemented universal hepatitis B immunization andexperienced measurable reductions in HBV-related disease. Forexample, in Taiwan, the prevalence of chronic infection in childrendeclined by more than 90%. Many resource-poor nations have recentlyinitiated universal hepatitis B immunization programs with assistancefrom the Global Alliance for Vaccines and Immunization. Furtherprogress towards the elimination of HBV transmission will requiresustainable vaccination programs with improved vaccination coverage,practical methods of measuring the impact of vaccination programs,and targeted vaccination efforts for communities at high riskof infection. hepatitis B • hepatitis B vaccines • hepatitis B virus • immunization programs