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.
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.
ABSTRACT
"Pharmacovigilance; defined as ""the science and activities relating to the detection; assessment; understanding and prevention of adverse effects or any other possible drug related problem""; is increasingly being recognized in Africa. Many African countries have simultaneously adopted artemisinin derivative based combination therapy (ACT) as first-line treatment for uncomplicated malaria; offering an opportunity to assess the safety of these drugs when used widely. While ACTs appear to be safe and well-tolerated; there is little experience with these medicines in Africa; outside clinical trials. Pharmacovigilance for ACTs and other combination treatments in Africa is essential. Malaria transmission intensity is high and antimalarial medicines are used frequently. Presumptive treatment of fever with antimalarials is common; often in the absence of a confirmed diagnosis; using drugs obtained without a prescription. Informal use of antimalarial drugs may increase the risk of incorrect dosing; inappropriate treatment; and drug interactions; which may impact negatively on drug safety. Furthermore; the administration of antimalarial treatments in patients with a concomitant illness; including HIV/AIDs; tuberculosis and malnutrition; is a concern. African countries are being encouraged to establish pharmacovigilance systems as ACTs are rolled out. However; pharmacovigilance is difficult; even in countries with a well-developed health care system. The rationale for pharmacovigilance of antimalarial drugs is discussed here; outlining the practical challenges and proposing approaches that could be adopted in Africa."
Subject(s)
Antimalarials/adverse effects , Fever , MalariaABSTRACT
Background: The vulnerability to contract malaria was researched among the Raglai ethnic minority population living in the mountainous areas of Ninh Thuan province, South-central Viet Nam, one of the areas with highest incidence rates in the country. Objective: To investigate the bed net use, risk perception of contracting malaria in Raglai ethnic minority. Subject and Method: The study used qualitative and quantitative method and was carried out in Ninh Thuan from 8/2005 to 8/2006. Result: Raglai exposure to malaria was related to farmers' forest activity and forest sleep which were directly related to the combination of sleeping and living in a government supported home in newly established villages along the road with a second home or reduced plot hut near fields in the forest to meet work requirements during the labor intensive malaria transmission and rainy season. In this context, access to health care, bed net use, risk perception of contracting malaria and health seeking behavior were researched. Conclusion: The results of the study do not only show the vulnerability of an impoverished ethnic minority population but as well the urgent need to better understand ethnic minorities' social context and culture to improve malaria control strategies.