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Efficacy of hepatitis B vaccine in the Gambian expanded programme on immunisation
M Fortuin1, J Chotard, A D Jack
1International Agency for Research on Cancer, The Gambia Hepatitis Intervention Study, Banjul.
Insights
Hepatitis B virus (HBV) vaccination in The Gambia is highly effective, showing 84% efficacy against infection and 94% against chronic carriage. This vaccination program offers hope for reducing future liver disease and cancer rates.
Area of Science:
- Immunology
- Public Health
- Virology
Background:
- Hepatitis B virus (HBV) infection is highly prevalent in The Gambia.
- HBV vaccination is part of the national immunization program.
- Assessing vaccine efficacy is crucial for public health strategies.
Purpose of the Study:
- To evaluate the efficacy of the hepatitis B vaccine.
- To determine the vaccine's effectiveness against HBV infection and chronic carriage.
- To identify risk factors for breakthrough infections.
Main Methods:
- A comparative study involving 720 vaccinated and 816 unvaccinated children aged 3-4 years.
- Assessment of HBV infection and chronic carriage status in both groups.
- Analysis of breakthrough infections in infants born to mothers with specific hepatitis B antigens.
Main Results:
- The HBV vaccine demonstrated 84% efficacy against infection (95% CI 78-89%).
- The vaccine showed 94% efficacy against chronic carriage (95% CI 84-98%).
- Infants of mothers positive for hepatitis B surface and e antigens had a higher risk of breakthrough infection.
Conclusions:
- The HBV vaccine is highly effective in preventing infection and chronic carriage in The Gambia.
- Vaccine efficacy provides a promising outlook for reducing HBV-related chronic liver disease and liver cancer.
- Targeted strategies may be needed for infants born to mothers with high viral load markers.
Abstract:
Because of the high prevalence of hepatitis B virus (HBV) infection in The Gambia, HBV vaccination has been incorporated into the national expanded programme on immunisation. We have assessed the efficacy of the vaccine against HBV infection and chronic carriage by examining 720 3-4-year-old children who had received the vaccine in infancy and 816 who had not received it. The vaccine was 84% (95% CI 78-89%) effective against infection and 94% (84-98%) effective against chronic carriage. Vaccinated infants of mothers positive for hepatitis B surface and e antigens were at greater risk of breakthrough infection and chronic carriage than infants of uninfected mothers. The high vaccine efficacy against the HBV carrier state, the main risk factor for the development of chronic liver disease and liver cancer, offers hope that the prevalence of these diseases may be reduced in the future.