title: Continuing Decrease in Hepatitis B Virus Infection 30 Years After Initiation of Infant Vaccination Program in Taiwan.
abstract: Taiwan began a universal hepatitis B virus (HBV) vaccination program for infants in July 1984. The seroprevalence of hepatitis B surface antigen (HBsAg) decreased from 9.8% before the vaccination program to less than 1% by 25 years afterward. We continued to monitor HBV infections in this population.
  
  
  
  We conducted a series of serologic and epidemiologic surveys in the Taipei metropolitan area every 5 years from 1984 through 2014. From January 1 through December 31 of 2014, we collected serum samples from 4605 apparently healthy individuals (ages: 287 were <3 y, 405 were 3-6 y, 675 were 7-12 y, 686 were 13-18 y, 468 were 18-22 y, and 2084 were 22-50 y). All subjects were tested for HBsAg, its antibody (anti-HBs), and hepatitis B core antibody (anti-HBc). We performed genotype and viral load analyses for patients who tested positive for anti-HBc.
  
  
  
  Of vaccinated participants (age, <30 y; n = 3299), 0.5% tested positive for HBsAg, 47.4% tested positive for anti-HBs, and 4.5% tested positive for anti-HBc. Of unvaccinated participants (age, 30-50 y, n = 1306), 6.7% tested positive for HBsAg (P < .0001), 69.4% tested positive for anti-HBs, and 44.1% tested positive for anti-HBc. One occult HBV infection was found in each age group. Among subjects positive for HBsAg younger than age 30, 77% were born to mothers positive for HBsAg.
  
  
  
  Based on a series of serologic and epidemiologic surveys performed in the Taipei metropolitan area, 6.7% of persons born before the universal HBV vaccination program were positive for HBsAg, compared with 0.5% of those born afterward. Most subjects positive for HBsAg younger than age 30 were born to mothers positive for HBsAg.
authors.affiliation: Department of Pediatrics, Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan; Hepatitis Research Center, Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan. Electronic address: yhni@ntu.edu.tw.
authors.forename: Yen-Hsuan
authors.initials: YH
authors.lastname: Ni
authors.affiliation: Department of Pediatrics, Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan; Hepatitis Research Center, Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Mei-Hwei
authors.initials: MH
authors.lastname: Chang
authors.affiliation: Department of Family Medicine, Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Chyi-Feng
authors.initials: CF
authors.lastname: Jan
authors.affiliation: Department of Pediatrics, Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Hong-Yuan
authors.initials: HY
authors.lastname: Hsu
authors.affiliation: Department of Pediatrics, Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Huey-Ling
authors.initials: HL
authors.lastname: Chen
authors.affiliation: Department of Pediatrics, Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Jia-Feng
authors.initials: JF
authors.lastname: Wu
authors.affiliation: Hepatitis Research Center, Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan; Genomics Research Center, Academica Sinica, Taipei, Taiwan.
authors.forename: Ding-Shinn
authors.initials: DS
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D005838:Genotype; D060005:Genotyping Techniques; D006509:Hepatitis B / Q000453:epidemiology* / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006515:Hepatitis B virus / Q000302:isolation & purification; D006801:Humans; D017589:Immunization Programs; D007223:Infant; D008297:Male; D008875:Middle Aged; D016036:Seroepidemiologic Studies; D013624:Taiwan / Q000453:epidemiology; D019562:Viral Load; D055815:Young Adult
chemical_list: D004279:DNA, Viral; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines
keywords: Immunization; Liver Disease; Prevention; Seroepidemiology