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PLoS One. 2013;8(3):e58029. doi: 10.1371/journal.pone.0058029. Epub 2013 Mar 22.

Observational study of vaccine efficacy 24 years after the start of hepatitis B vaccination in two Gambian villages: no need for a booster dose.

Author information

1
Medical Research Council Laboratories, The Gambia, Banjul, the Gambia, West Africa. mendym@iarc.fr

Abstract

OBJECTIVES:

To determine the duration of protection from hepatitis B vaccine given in infancy and early childhood and asses risk factors for HBV infection and chronic infection.

METHODS:

In 1984 infant HBV vaccination was started in two Gambian villages. Cross sectional serological surveys have been undertaken every 4 years to determine vaccine efficacy. In the current survey 84.6% of 1508 eligible participants aged 1-28 years were tested. A spouse study was conducted in females (aged 14 years and above) and their male partners.

RESULTS:

Vaccine efficacy against chronic infection with hepatitis B virus was 95.1% (95% confidence interval 91.5% to 97.1%), which did not vary significantly between age groups or village. Efficacy against infection was 85.4% (82.7% to 87.7%), falling significantly with age. Concentrations of hepatitis B antibody fell exponentially with age varying according to peak response: 20 years after vaccination only 17.8% (95% CI 10.1-25.6) of persons with a low peak response (10-99 mIU/ml) had detectable HBs antibody compared to 27% (21.9% to 32.2%) of those with a high peak response (>999 mIU/ml). Time since vaccination and a low peak response were the strongest risk factors for HBV infections; males were more susceptible, marriage was not a significant risk for females. Hepatitis B DNA was not detected after infection, which tested soley core antibody positive. An undetectable peak antibody response of <10 mIU/ml and a mother who was hepatitis B e antigen positive were powerful risk factors for chronic infection.

CONCLUSIONS:

Adolescents and young adults vaccinated in infancy are at increased risk of hepatitis B infection, but not chronic infection. Married women were not at increased risk. There is no compelling evidence for the use of a booster dose of HBV vaccine in The Gambia.

PMID:
23533578
PMCID:
PMC3606345
DOI:
10.1371/journal.pone.0058029
[Indexed for MEDLINE]
Free PMC Article

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