title: Hepatitis B virus infection in children and adolescents in a hyperendemic area: 15 years after mass hepatitis B vaccination.
abstract: BACKGROUND
  Hepatitis B virus (HBV) infection is hyperendemic in Taiwan. Before universal HBV immunization was started in Taiwan in 1984, the carrier rate for hepatitis B surface antigen (HBsAg) was 15% to 20% in the general population.
  
  
  OBJECTIVE
  To quantify the population impact of a mass vaccination program for HBV 15 years after its implementation.
  
  
  METHODS
  Descriptive analysis of serologic markers of HBV in healthy children and adolescents.
  
  
  METHODS
  Chung-Cheng District, Taipei City, Taiwan, in 1999.
  
  
  METHODS
  1357 persons younger than 15 years of age, who were born after the implementation of universal HBV vaccination, and 559 persons 15 to 20 years of age, who were born before the program began.
  
  
  METHODS
  Repeated serologic surveys similar to those done before and 5 and 10 years after the national vaccination program was implemented. All participants were tested for serum HBsAg, its antibody (anti-HBs), and hepatitis B core antibody (anti-HBc).
  
  
  RESULTS
  During the 15 years since the vaccination program was implemented, the prevalence of HBsAg among persons younger than 15 years of age decreased from 9.8% in 1984 to 0.7% in 1999; among persons 15 to 20 years of age, the 1999 prevalence of HBsAg was 7% (P < 0.001). Hepatitis B core antibody seropositivity, which represents HBV infection, was found in 2.9% of persons younger than 15 years of age and in 20.6% of persons 15 to 20 years of age (P < 0.001); in the same age groups, the rate of anti-HBs seropositivity was 75.8% and 70.7%, respectively (P = 0.02).
  
  
  CONCLUSIONS
  Universal vaccination significantly decreased the HBV carrier rate and infection rate among children and adolescents born since the program began. By decreasing the carrier pool, continuation of the national HBV immunization program should prevent HBV infection in the children of Taiwan, and, subsequently, adults as well.
authors.affiliation: National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 100, Taiwan.
authors.forename: Y H
authors.initials: YH
authors.lastname: Ni
authors.forename: M H
authors.initials: MH
authors.lastname: Chang
authors.forename: L M
authors.initials: LM
authors.lastname: Huang
authors.forename: H L
authors.initials: HL
authors.lastname: Chen
authors.forename: H Y
authors.initials: HY
authors.lastname: Hsu
authors.forename: T Y
authors.initials: TY
authors.lastname: Chiu
authors.forename: K S
authors.initials: KS
authors.lastname: Tsai
authors.forename: D S
authors.initials: DS
authors.lastname: Chen
mesh_terms: D005260:Female; D005500:Follow-Up Studies; D006509:Hepatitis B / Q000453:epidemiology* / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood; D006512:Hepatitis B Core Antigens / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000276:immunology; D017325:Hepatitis B Vaccines; D006801:Humans; D008297:Male; D016036:Seroepidemiologic Studies; D013624:Taiwan / Q000453:epidemiology; D014611:Vaccination
chemical_list: D006510:Hepatitis B Antibodies; D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines