title: Long-term protection against HBV chronic carriage of Gambian adolescents vaccinated in infancy and immune response in HBV booster trial in adolescence.
abstract: BACKGROUND
  Chronic infection with hepatitis B virus (HBV) arising in childhood is associated with hepatocellular carcinoma in adult life. Between 1986 and 1990, approximately 120,000 Gambian newborns were enrolled in a randomised controlled trial to assess the effectiveness of infant HBV vaccination on the prevention of hepatocellular carcinoma in adulthood. These children are now in adolescence and approaching adulthood, when the onset of sexual activity may challenge their hepatitis B immunity. Thus a booster dose in adolescence could be important to maintain long-term protection.
  
  
  METHODS
  Fifteen years after the start of the HBV infant vaccination study, 492 vaccinated and 424 unvaccinated children were identified to determine vaccine efficacy against infection and carriage in adolescence. At the same time, 297 of the 492 infant-vaccinated subjects were randomly offered a booster dose of HBV vaccine. Anti-HBs was measured before the booster, and two weeks and 1 year afterwards (ISRCTN71271385).
  
  
  RESULTS
  Vaccine efficacy 15 years after vaccination was 67.0% against infection as manifest by anti-HBc positivity (95% CI 58.2-74.6%), and 96.6% against HBsAg carriage (95% CI 91.5-100%). 31.2% of participants had detectable anti-HBs with a GMC of 32 IU/l. For 168 boosted participants GMC anti-HBs responses were 38 IU/l prior to vaccination, 524 IU/l two weeks after boosting, and 101 IU/l after 1 year.
  
  
  CONCLUSIONS
  HBV vaccination in infants confers very good protection against carriage up to 15 years of age, although a large proportion of vaccinated subjects did not have detectable anti-HBs at this age. The response to boosting persisted for at least a year.
  
  
  BACKGROUND
  Controlled-Trials.com ISRCTN71271385.
authors: Medical Research Council Laboratories, Fajara, The Gambia. Marianne.van.der.sande@rivm.nl
authors: Marianne A B
authors: MA
authors: van der Sande
authors: Pauline A
authors: PA
authors: Waight
authors: Maimuna
authors: M
authors: Mendy
authors: Syed
authors: S
authors: Zaman
authors: Steve
authors: S
authors: Kaye
authors: Omar
authors: O
authors: Sam
authors: Abi
authors: A
authors: Kahn
authors: David
authors: D
authors: Jeffries
authors: Aveika A
authors: AA
authors: Akum
authors: Andrew J
authors: AJ
authors: Hall
authors: Ebrima
authors: E
authors: Bah
authors: Samuel J
authors: SJ
authors: McConkey
authors: Pierre
authors: P
authors: Hainaut
authors: Hilton C
authors: HC
authors: Whittle
mesh_terms: D000293:Adolescent; D000328:Adult; D006528:Carcinoma, Hepatocellular / Q000209:etiology / Q000821:virology; D002648:Child; D005260:Female; D005714:Gambia; D006509:Hepatitis B / Q000150:complications / Q000276:immunology* / Q000517:prevention & control*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage / Q000276:immunology; D006521:Hepatitis, Chronic / Q000150:complications / Q000276:immunology* / Q000517:prevention & control*; D006801:Humans; D007117:Immunization, Secondary; D007223:Infant; D008113:Liver Neoplasms / Q000209:etiology / Q000821:virology; D008297:Male; D016896:Treatment Outcome
chemical_list: D017325:Hepatitis B Vaccines
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