The world’s first vaccine against malaria could be in use within two years. British drug maker GlaxoSmithKline says it is seeking regulatory approval for the new vaccine following positive results from clinical trials in Africa.

Malaria is still a major scourge in the developing world, killing around 660,000 people a year — most of them children in sub-Saharan Africa.

In clinical trials in seven African countries, Glaxo’s vaccine, known as RTS,S, proved quite effective in combating the disease. It cut by half the number of malaria cases in young children.

The Bill and Melinda Gates Foundation helped finance the development of the new medicine. If approved, it will be sold at cost price plus 5 percent to finance further research. But the Oxfam Aid Agency claims that may yet prove too expensive.

“Malaria hits the poorest countries and the poorest people in those countries. So this vaccine, if proven effective, needs to be affordable. It really does have to be very low cost,” says Oxfam’s Anna Marriott.

Some experts in tropical diseases are also giving the vaccine a rather cautious welcome. They point out that since it has taken at least 15 years to get this far, it could still be many years before the new treatment is in widespread use.