Long-term protection against HBV chronic carriage of Gambian adolescents vaccinated in infancy and immune response in HBV booster trial in adolescence.
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.
van der Sande
Marianne A B
MA
Medical Research Council Laboratories, Fajara, The Gambia. Marianne.van.der.sande@rivm.nl
Waight
Pauline A
PA
Mendy
Maimuna
M
Zaman
Syed
S
Kaye
Steve
S
Sam
Omar
O
Kahn
Abi
A
Jeffries
David
D
Akum
Aveika A
AA
Hall
Andrew J
AJ
Bah
Ebrima
E
McConkey
Samuel J
SJ
Hainaut
Pierre
P
Whittle
Hilton C
HC
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
D017325:Hepatitis B Vaccines
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