title: Genetic variations of hepatitis B virus.
abstract: The emergence of hepatitis B virus genetic variants occurs under the influence of host immunity, immunization, the use of immune globulin or antiviral chemotherapy. Most of these are probably the result of the 'immune escape' phenomenon. Some variants, in particular those in the precore and core promoter regions, have been associated with disease severity and progression. Surface antigen variants have implications for the accuracy of laboratory diagnosis and may reduce the effectiveness of vaccination. Polymerase variants are selected as a result of the use of antiviral chemotherapeutic agents. It is important to monitor the occurrence of these variants.
authors.affiliation: Virology Section, Department of Infection, St Thomas Hospital, London, UK.
authors.forename: C.Y. William
authors.initials: CY
authors.lastname: Tong