title: Population-based interventions to reduce the public health burden related with hepatitis B virus infection in the gambia, west Africa.
abstract: In The Gambia, West Africa, the prevalence of chronic hepatitis B virus (HBV) infection in adults exceeds eight percent and hepatocellular carcinoma (HCC) has been the most frequent type of malignancy. Two population-based intervention studies to control HBV infection, namely, GHIS (Gambia Hepatitis Intervention Study) and PROLIFICA (Prevention of Liver Fibrosis and Cancer in Africa), are discussed. The GHIS started in 1986 as a nation-wide trial of the HBV vaccine to evaluate the effectiveness of infant HBV vaccination in preventing HCC in adulthood. The vaccine was progressively introduced into the Expanded Program of Immunization (EPI) of The Gambia over four years in a phased manner, called the "stepped-wedge" design. This was because instantaneous universal vaccination in the country was impossible for logistic and financial reasons. However, this design also allowed the study to have an unvaccinated control group which consisted of the newborns of the areas where HBV vaccine has not yet been incorporated in the EPI. To assess the outcome, a national cancer registry was founded and all HCC patients in this birth cohort are linked with the vaccine trial database. The study is still ongoing to answer whether the HBV vaccine in infancy prevent HCC in adulthood in The Gambia. Although the universal HBV vaccination since 1990 has been successful in reducing the prevalence of chronic HBV infection in young Gambians, the number of HCC cases may not decline over the next decades as people infected prior to the immunization program are likely to continue to develop the diseases. To reduce the HCC incidence through community-based screening of HBV infection and provision of antiviral therapy, the PROLIFICA project started in 2011. Study hypothesis and design of these two studies, GHIS and PROLIFICA, are further discussed.
authors.affiliation: Medical Research Council (MRC) Unit, The Gambia, Atlantic Boulevard, Fajara , P.O. Box 273, Banjul, The Gambia ; Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine , Keppel Street, London, WC1E 7HT, UK.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Shimakawa
authors.affiliation: Medical Research Council (MRC) Unit, The Gambia, Atlantic Boulevard, Fajara , P.O. Box 273, Banjul, The Gambia ; Department of Hepatology, Imperial College London , UK, Norfolk Place, London, W2 1NY, UK.
authors.forename: Maud
authors.initials: M
authors.lastname: Lemoine
authors.affiliation: International Agency for Research on Cancer (IARC) . 150 Cours Albert Thomas, 69372 Lyon CEDEX 08, France.
authors.forename: Maimuna
authors.initials: M
authors.lastname: Mendy
authors.affiliation: Medical Research Council (MRC) Unit, The Gambia, Atlantic Boulevard, Fajara , P.O. Box 273, Banjul, The Gambia.
authors.forename: Harr Freeya
authors.initials: HF
authors.lastname: Njai
authors.affiliation: Medical Research Council (MRC) Unit, The Gambia, Atlantic Boulevard, Fajara , P.O. Box 273, Banjul, The Gambia.
authors.forename: Umberto
authors.initials: U
authors.lastname: D'Alessandro
authors.affiliation: International Agency for Research on Cancer (IARC) . 150 Cours Albert Thomas, 69372 Lyon CEDEX 08, France.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hall
authors.affiliation: Department of Hepatology, Imperial College London , UK, Norfolk Place, London, W2 1NY, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Thursz
authors.affiliation: Medical Research Council (MRC) Unit, The Gambia, Atlantic Boulevard, Fajara , P.O. Box 273, Banjul, The Gambia ; Gambia Hepatitis Intervention Study (GHIS), IARC, c/o MRC Unit, The Gambia, Atlantic Boulevard, Fajara , P.O. Box 273, Banjul, The Gambia.
authors.forename: Ramou
authors.initials: R
authors.lastname: Njie
keywords: Africa; Hepatitis B; The Gambia; antiviral agents; carcinoma; epidemiology; hepatitis B vaccines; hepatocellular; public health