Millions of deaths a year could be prevented by a new malaria vaccine that has been shown to cut the risk of disease in young children by half.
The initial results from a final stage of vaccine testing were released yesterday, and the vaccine's developers hailed the results in helping to tame one of the world's most devastating killers.
Bill Gates, whose foundation has contributed $1.75bn to the effort, said it was a "huge milestone" in the fight against the disease.
"This is proof that it is possible to create a vaccine that is effective against malaria," he said. He added that it "has the potential to protect millions of children and save thousands of lives".
However, the vaccine won't be available for at least three years, as crucial further testing must be completed to see how well it works in infants and how long protection lasts. Then the vaccine must be reviewed by government agencies in Europe and in individual African countries.
"We still have a way to go," Tsiri Agbenyega, lead researcher for the African study, said in a conference call with reporters.
The early results, taken from a study in seven African countries, show the vaccine is only about 50 per cent effective, significantly lower than the protection seen in more common vaccines. But some experts said it's a vast improvement on the current situation, and could still save hundreds of thousands of lives.
Globally, malaria kills nearly a million people annually. More than 90 per cent of them live in Africa, and most are young children and pregnant women.
Scientists have been trying for decades to develop a malaria vaccine and the one tested – which was developed by GlaxoSmithKline – is furthest along. Without a vaccine, public health efforts have concentrated on malaria drugs and other ways to prevent infection such as mosquito bed netting and insecticides.
The new vaccine targets a malaria parasite found in sub-Saharan Africa. Malaria spreads through mosquitoes, which bite people and flush malaria parasites into the bloodstream.
The new study – still under way – began in 2009 and involves more than 15,000 children in Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique and Tanzania. Early results were released yesterday at a malaria conference in Seattle and published by The New England Journal of Medicine.
The findings focus on about 6,000 children aged five to 17 months. A year after getting three doses, the vaccinated children had about half as many cases of malaria as a group that didn't get the vaccine.
No price has been set for the Glaxo vaccine. Chief executive Andrew Witty pledged the company will price it as low as possible.