title: HBV infection in indigenous children, 20 years after immunization in Taiwan: a community-based study.
abstract: OBJECTIVE
  Hepatitis B virus infection is hyperendemic in Taiwan. In the past, the infection rate has been higher in indigenous villages. The prevalence of chronic HBV infection among indigenous children after immunization remains unknown.
  
  
  METHODS
  A total of 843 indigenous children were checked for the hepatitis B seromarker. Another 606 metropolitan children were enrolled for comparison in 2005.
  
  
  RESULTS
  The seroprevalences (%) of HBsAg, (hepatitis B surface antigen) anti-HBs, (antibody to hepatitis B surface antigen) and anti-HBc (antibody to hepatitis B core antigen) among indigenous and metropolitan children were 3.2 vs. 0.17 (p<0.001), 47.4 vs. 51.2 (p=0.164), and 10.7 vs. 1.7 (p<0.001), respectively. Among the indigenous children, who were divided into three age groups, the prevalences of HBsAg and anti-HBc increased with age, while anti-HBs decreased significantly (p=0.025, 0.002, and <0.001, respectively). Children with positive HBsAg had a significantly higher mean (SD) age (10.2 (2.2) vs. 9.2 (2.1) years, p=0.024) and a higher ALT value (16.4 (8.0) vs. 10.6 (8.3) IU/L, p=0.001). In a multivariable analysis, indigenous residency, older age group and abnormal ALT value were independent factors associated with positive HBsAg.
  
  
  CONCLUSIONS
  The seroprevalence of hepatitis B infection has obviously declined among indigenous children 20 years after mass immunization programs launched in Taiwan. However, it is still higher than that of metropolitan children. Higher rates of chronic HBV infection in the mothers might be one important explanation for this finding.
authors.affiliation: Department of Occupational and Environmental Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Chung-Feng
authors.initials: CF
authors.lastname: Huang
authors.forename: Chia-Yen
authors.initials: CY
authors.lastname: Dai
authors.forename: Wan-Long
authors.initials: WL
authors.lastname: Chuang
authors.forename: Chi-Kung
authors.initials: CK
authors.lastname: Ho
authors.forename: Ta-Chung
authors.initials: TC
authors.lastname: Wu
authors.forename: Nai-Jen
authors.initials: NJ
authors.lastname: Hou
authors.forename: Chao-Ling
authors.initials: CL
authors.lastname: Wang
authors.forename: Ming-Yen
authors.initials: MY
authors.lastname: Hsieh
authors.forename: Jee-Fu
authors.initials: JF
authors.lastname: Huang
authors.forename: Zu-Yau
authors.initials: ZY
authors.lastname: Lin
authors.forename: Shinn-Cherng
authors.initials: SC
authors.lastname: Chen
authors.forename: Ming-Yuh
authors.initials: MY
authors.lastname: Hsieh
authors.forename: Liang-Yen
authors.initials: LY
authors.lastname: Wang
authors.forename: Jun-Fa
authors.initials: JF
authors.lastname: Tsai
authors.forename: Wen-Yu
authors.initials: WY
authors.lastname: Chang
authors.forename: Ming-Lung
authors.initials: ML
authors.lastname: Yu
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology* / Q000208:ethnology* / Q000276:immunology; D006510:Hepatitis B Antibodies / Q000276:immunology; D006514:Hepatitis B Surface Antigens / Q000276:immunology; D017325:Hepatitis B Vaccines; D006515:Hepatitis B virus / Q000276:immunology*; D006801:Humans; D007114:Immunization; D008297:Male; D015995:Prevalence; D012189:Retrospective Studies; D016036:Seroepidemiologic Studies; D012698:Serologic Tests; D013624:Taiwan / Q000453:epidemiology
chemical_list: D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines