Malaria vaccine shows promise, cuts risk by half

(CBS/AP) The world's first malaria vaccine just got one step closer.

Shots of an experimental vaccine halved the risk of the disease in young children, according to a new study released Tuesday.

The results are a milestone in helping to tame one of the world's most devastating killers, say the vaccine's developers. But the vaccine won't be available for at least three years - further testing must be done to see how well it works in infants and how long protection lasts. And then the vaccine must be reviewed by government agencies in Europe and in Africa.

"We still have a way to go," Tsiri Agbenyega, lead researcher for the African study, said in a conference call with reporters.

Worldwide, malaria kills nearly a million people a year. More than 90 percent of them live in Africa, and most are young children and pregnant women.

The vaccine is significantly less effective than more common vaccines, but a vast improvement over the current situation, experts say. It could save hundreds of thousands of lives.

Malaria spreads through mosquitoes, which bite people and flush malaria parasites into the bloodstream. The parasites cause bouts of high fever and can end in fatal organ failure. There are five species of malaria parasites, and the new vaccine is designed specifically to protect against the deadliest one, which is common in sub-Saharan Africa.

The ongoing study began in 2009 and involves more than 15,000 children in Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique and Tanzania. A year after three doses, the vaccinated children had about half as many cases of malaria as a group that didn't get the vaccine.

For decades, scientists have been trying to develop a malaria vaccine - this one, tested by GlaxoSmithKline, is furthest along. Without a vaccine, efforts have concentrated on malaria drugs and other ways to prevent infection such as mosquito bed netting and insecticides.