title: Long term immune response of universal hepatitis B vaccination in infancy: a community-based study in Taiwan.
abstract: OBJECTIVE
  To evaluate the long term immunity provided by a universal hepatitis B vaccination program in infancy and the booster effect on school age children who had no protective antibody titers to hepatitis B surface antigen.
  
  
  METHODS
  We conducted a community-based seroepidemiologic study of 1337 healthy 7-year-old children in Taiwan one decade after the implementation of a mass hepatitis B vaccination program. A booster vaccination was suggested for noncarrier children who did not have protective titers of surface antibody. Serologic responses and infection rates were compared with those of the nonboostered children. In a nonselected group of 39 volunteer noncarrier vaccinees, quantitative serologic response was determined before, 1 month after a booster vaccination and 1 year later.
  
  
  RESULTS
  A total of 572 children (42.8%) had low concentrations of surface antibody, and 9 were hepatitis B surface antigen carriers (0.7%). Eighty-two percent of "nonprotected" vaccinees showed immunologic memory to a booster dose and developed protective antibody titers 1 month later; 60.6% maintained protective titers 1 year later. The frequency of new hepatitis B virus infection was similar for those who received a booster and those who did not as investigated by the core antibody seroconversion during 1-year follow-up. However, the risk was low, with annual incidences of <1% in both groups, and none became chronic carriers.
  
  
  CONCLUSIONS
  According to these data a universal vaccination program in infancy provides adequate protection against hepatitis B virus infection for school age children and a booster vaccination is not recommended.
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital, Taipei.
authors.forename: H H
authors.initials: HH
authors.lastname: Shih
authors.forename: M H
authors.initials: MH
authors.lastname: Chang
authors.forename: H Y
authors.initials: HY
authors.lastname: Hsu
authors.forename: P I
authors.initials: PI
authors.lastname: Lee
authors.forename: Y H
authors.initials: YH
authors.lastname: Ni
authors.forename: D S
authors.initials: DS
authors.lastname: Chen
mesh_terms: D002648:Child; D005260:Female; D006509:Hepatitis B / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood*; D006514:Hepatitis B Surface Antigens / Q000276:immunology; D017325:Hepatitis B Vaccines / Q000008:administration & dosage / Q000276:immunology*; D006801:Humans; D017589:Immunization Programs; D007117:Immunization, Secondary; D007156:Immunologic Memory; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D013624:Taiwan
chemical_list: D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines