There are about 94 clinical studies being (or have been) conducted in Gambia. The country of the clinical trial is determined by the location of where the clinical research is being studied. Most studies are often held in multiple locations & countries.
Severe anaemia is a frequent cause of admission to hospitals in tropical Africa and about 10% of such children die. In endemic countries, anaemia has multiple causes such as nutritional deficiencies, infections and haemoglobinopathies. However, Plasmodium falciparum infection is believed to be the major contributory factor to the aetiology of severe anaemia. Severe anaemia is usually treated by blood transfusion although transfusion carries the attendant risk of transmission of HIV and other blood-borne infections. Thus, there is a need to explore novel strategies to reduce the incidence of severe anaemia in high-risk groups such as children with suboptimal haemoglobin levels because these children are at increased risk of developing severe anaemia if they develop a malaria infection before their haemoglobin level has normalized. Therefore, it is proposed to study whether monthly chemoprophylaxis with sulphadoxine/pyrimethamine (S/P) given during malaria transmission season can protect Gambian children from developing severe anaemia. After receiving treatment from the hospital, 1200 children admitted to the hospital with a haematocrit of less than 21% were randomised to receive either monthly S/P or placebo during the rest of the malaria transmission season. Morbidity was monitored throughout the rainy season. Study subjects were seen at the end of the dry season to document morbidity and mortality.
There are new TB vaccines already developed that need to be tried in humans to assess their efficacy. The researchers had previously shown that production of interferon gamma by T cells in response to TB antigens is a more specific marker of TB infection. The researchers hypothesize that this can be used as a reliable early marker of TB vaccine efficacy. The researchers expect to show a significantly increased reversion of this test in household contacts of TB patients given Isoniazid prophylaxis treatment for 6 months.
The ability to test candidate pre-erythrocytic stage malaria vaccines, using a well-established sporozoite challenge model, in a field setting with group sizes of tens rather than hundreds of volunteers would greatly facilitate identification of the most promising vaccine candidates. The investigators assessed the suitability and acceptability of this method in a field trial in semi-immune volunteers exposed to natural infection during the high malaria transmission season.
Animal and human studies have shown that the prime-boost immunization strategy using malaria antigens expressed in plasmid or viral vectors induces strong cellular immune responses. An immunization regimen with the malaria vaccines DNA ME-TRAP followed by MVA ME-TRAP induced strong T cell responses in adults in the United Kingdom (UK) and in the Gambia but did not provide significant clinical protection against infection. The investigators assessed two new vaccines which utilize a similar immunization strategy but a different malaria antigen, a circumsporozoite (CS) protein. The entire CS protein was expressed either in a modified vaccinia virus Ankara (MVA) CS, or an attenuated fowlpox virus strain (FP9) CS.
Supplementation with folic acid and iron is recommended for pregnant women in order to prevent them from developing anemia. In malaria endemic areas of Africa, the World Health Organization (WHO) now recommends that pregnant women should also be given sulfadoxine-pyrimethamine (SP) once a month after quickening to protect them against malaria which is especially harmful during pregnancy. However, folic acid is an antagonist of SP so there is a possibility that giving folic acid with SP could interfere with the ability of the latter to provide protection against malaria. To investigate this possibility Gambian primigravidae with malaria parasitemia have been given SP and folic acid at the same time or on separate occasions two weeks apart and the ability of SP to cure the malaria infection investigated.
Malaria is particularly harmful during pregnancy causing anemia in the mother and low birth weight which, in turn, increases infant mortality. Thus, the World Health Organization (WHO) now recommends that all pregnant women who live in malaria endemic areas of Africa should receive sulfadoxine-pyrimethamine (SP) at monthly intervals during the second and third trimesters of pregnancy. Malaria is especially severe during first pregnancies and the value of intermittent preventative treatment with SP during first pregnancies has been clearly shown. However, it is less certain whether multigravidae, who are at less risk, also benefit from intermittent preventative treatment with SP. To investigate this, a trial has been conducted in Gambian multigravidae who were given intermittent preventative treatment with SP or placebo during the second and third trimesters. The prevalence of anemia six weeks after delivery, low birth weight and poor outcome of pregnancy in women in each group were studied.
The purpose of this trial is to compare the effectiveness of three combination treatments for uncomplicated malaria when given in operational settings, without supervision of doses other than the first dose.
Lapdap (chlorproguanil-dapsone) is an affordable and effective drug, but patients with glucose-6-phosphate dehydrogenase (G6PD) A- deficiency are more susceptible to the haemolytic effects of the dapsone component of Lapdap; therefore there is a need to evaluate the extent to which the risks associated with the use of the drug in settings without G6PD screening might outweigh the benefits to malaria treatment. The investigators will evaluate, in operational settings, the safety and effectiveness of Lapdap and coartemether (lumefantrine-artemether) for treatment of uncomplicated malaria in patients 6 months to 10 years of age.