Project moves closer to malaria vaccine for children

An injection of more than US $100 million from the Bill & Melinda Gates Foundation this week has helped a public-private partnership project move closer to developing a paediatric malaria vaccine. The $107.6 million grant to the Malaria Vaccine Initiative (MVI) of the international NGO, Programme for Appropriate Technology in Health (PATH), will help its collaboration with GlaxoSmithKline Biologicals (GSK Bio) in developing RTS,S, the world's most advanced malaria vaccine candidate for children in Africa. "Between 2,000 to 4,000 children die of malaria every day in sub-Saharan Africa," said Ripley Ballou, head of GSK Bio's Emerging Diseases programme, which is working to develop vaccines against malaria, TB, HIV and cancer. A co-creator of the RTS,S vaccine, Ballou spent 20 years investigating malaria at the US army's Walter Reed Army Institute of Research. After proving the efficacy of RT,S in clinical trials among adults in the US, research on the vaccine has moved on to assess its impact on children. Ballou pointed out that the disease was a "bigger problem for children, who are most likely to die compared to adults living in malarious areas, who develop immunity". About five years ago, GSK Bio, MVI and Mozambique's ministry of health sponsored clinical trials of the vaccine on 2,022 children, conducted by the Manhica Health Research Centre. GSK Bio said the Mozambique site was choosen because it had "an excellent track record of high-quality relevant malaria research", with the ability to deliver good medical care to the study population, provided by experienced clinical investigators. According to MVI, the RT,S vaccine targets the malaria-causing parasite transmitted by mosquitoes. The antibodies and white blood cells produced after immunisation prevent the parasite from surviving or developing. The results of the southern Mozambique trial, published last year in the British medical journal, The Lancet, showed that the vaccine was effective in 30 percent of cases, efficacy against infection was 45 percent, and against severe disease 58 percent. Ballou said any percentage of impact on the disease was significant, "whether it is between 30 to 60 percent - it is a huge impact" on a disease that killed so many children every day. Since the numbers in the Mozambican clinical trial were "too small" to provide definitive proof of the efficacy of the vaccine in reducing malaria deaths among children, the project will conduct small-scale trials in several African countries in the next two years. "We also need to establish its impact in various strains and climatic conditions", he pointed out. The African sites are in the process of being identified and finalised, but only Mozambique and Tanzania have been confirmed so far, Ballou told IRIN. In 2008 the project will proceed to a large-scale Phase III trial involving 8,000 to 10,000 children aged under two. "We still have another five years of trials before we apply for a licence [for the vaccine], possibly in 2010 to 2011, subject to the review process, of course," he said. According to the World Health Organisation (WHO), malaria is by far the world's most important tropical parasitic disease, and kills more people than any other communicable disease except tuberculosis. The disease is a public health problem today in more than 90 countries, but the vast majority of malaria deaths occur in Africa south of the Sahara. Malaria has been estimated to cost Africa more than $12 billion every year in lost Gross Domestic Product, even though it could be controlled for a fraction of that sum. Malaria is the cause of 20 percent of under-five deaths in Africa and constitutes 10 percent of the continent's overall disease burden. It accounts for between 30 percent and 50 percent of inpatient admissions, and up to 50 percent of outpatient visits in areas with high malaria transmission.