title: The end of the Australia antigen? An ecological study of the impact of universal newborn hepatitis B vaccination two decades on.
abstract: BACKGROUND
  A universal newborn hepatitis B (HBV) vaccination program was introduced in the Northern Territory of Australia in 1990, followed by a school-based catch-up program. We evaluated the prevalence of hepatitis B infection in birthing women up to 20 years after vaccination and compared this to women born before the programs commenced.
  
  
  METHODS
  A cohort of birthing mothers was defined from Northern Territory public hospital birth records between 2005 and 2010 and linked to laboratory confirmed notifications of chronic HBV, based principally on a record of hepatitis B surface antigen detection. Prevalence of HBV was compared between women born before or after implementation of the newborn and catch-up vaccination programs.
  
  
  RESULTS
  Among 10797 birthing mothers, 138 (1.3%) linked to a chronic HBV record. HBV prevalence was substantially higher in Aboriginal women compared to non-Indigenous women (2.4% versus 0.04%; p<0.001). Among 5678 Aboriginal women, those eligible for catch-up and newborn HBV vaccination programs had a significantly lower HBV prevalence than older women born prior to the programs: HBV prevalence respectively 2.2% versus 3.5%, (OR 0.61, 95%CI 0.43-0.88) and 0.8% versus 3.5% (OR 0.21, 95%CI 0.11-0.43). This represents a risk reduction of respectively 40% and 80% compared to unvaccinated women.
  
  
  CONCLUSIONS
  The progressively greater reduction in the prevalence of chronic HBV in adult Aboriginal women co-inciding with eligibility for catch-up and newborn vaccination programs is consistent with a significant impact from both programs. The use of data derived from antenatal screening to track ongoing vaccine impact is applicable to a range of settings globally.
authors.affiliation: The Kirby Institute, University of New South Wales, Sydney, Australia. bliu@kirby.unsw.edu.au
authors.forename: Bette
authors.initials: B
authors.lastname: Liu
authors.forename: Steven
authors.initials: S
authors.lastname: Guthridge
authors.forename: Shu Qin
authors.initials: SQ
authors.lastname: Li
authors.forename: Peter
authors.initials: P
authors.lastname: Markey
authors.forename: Vicki
authors.initials: V
authors.lastname: Krause
authors.forename: Peter
authors.initials: P
authors.lastname: McIntyre
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Sullivan
authors.forename: James
authors.initials: J
authors.lastname: Ward
authors.forename: Nicholas
authors.initials: N
authors.lastname: Wood
authors.forename: John M
authors.initials: JM
authors.lastname: Kaldor
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology* / Q000517:prevention & control*; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D006801:Humans; D007231:Infant, Newborn; D015876:Northern Territory / Q000453:epidemiology; D015995:Prevalence; D014611:Vaccination / Q000379:methods*
chemical_list: D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines