title: Stable seroepidemiology of hepatitis B after universal immunization in Taiwan: A 3-year study of national surveillance of primary school students.
abstract: BACKGROUND
  This study is aimed to investigate if there was increased risk of HBV acquisition among first graders in Taiwan during a 3-year follow-up period.
  
  
  METHODS
  A total of 1545 healthy first graders, who were vaccinated against HBV in infancy, were recruited in 2005. All subjects were checked for hepatitis B surface antigens (HBsAg), antibodies to HBsAg (anti-HBs), and to the hepatitis B core antigen (anti-HBc). Nucleotide sequence of the "a" determinant of HBsAg was determined by polymerase chain reaction and direct sequencing in the HBsAg carriers.
  
  
  RESULTS
  Among 1545 subjects, 0.78% were HBsAg seropositive, 54.30% were anti-HBs seropositive, and 1.68% anti-HBc seropositive. Three of the 10 HBV carriers (30%), whose HBV DNA were sequenced for the S gene, had surface antigen mutants at the "a" determinant.
  
  
  CONCLUSIONS
  There were no new chronic HBV infections in this cohort of children for two consecutive years. HBV S gene vaccine escape mutants did exist in the vaccine-failure population, but they may not have made a major health impact.
authors.affiliation: Department of Pediatrics, College of Medicine and Children's Hospital, National Taiwan University, Taipei 100, Taiwan.
authors.forename: Ching-Yi
authors.initials: CY
authors.lastname: Chen
authors.forename: Hong-Yuan
authors.initials: HY
authors.lastname: Hsu
authors.forename: Cheng-Chuan
authors.initials: CC
authors.lastname: Liu
authors.forename: Mei-Hwei
authors.initials: MH
authors.lastname: Chang
authors.forename: Yen-Hsuan
authors.initials: YH
authors.lastname: Ni
mesh_terms: D002353:Carrier State / Q000453:epidemiology; D002648:Child; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology* / Q000235:genetics; D006510:Hepatitis B Antibodies / Q000097:blood; D006512:Hepatitis B Core Antigens / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D016036:Seroepidemiologic Studies; D013624:Taiwan / Q000453:epidemiology
chemical_list: D004279:DNA, Viral; D006510:Hepatitis B Antibodies; D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines