Hundreds of children are taking part in a malaria vaccine trial in six African countries. The U.N. says the mosquito-borne disease claims more than one-million lives globally each year, 90 percent of them in sub-Saharan Africa, and the vast majority children.

Poverty and lack of organization have frustrated Africa's efforts to control malaria's spread with low-tech means - such as spreading oil on stagnant ponds where mosquitoes breed and distributing window screens and bed nets.

Now, a vaccine program, sponsored in part by the Belgium-based pharmaceutical company GlaxoSmithKline Biologicals, is showing promising signs for many African countries.

In Ghana, for example, the government spends about a third of its annual health budget on treating malaria.

Dr. Jennifer Evans, a member of the local research team in Ghana, said results from similar studies in Mozambique, in which over 2,000 children participated, showed the vaccine to be effective for at least 18 months. She says cases of clinical malaria declined by 35 percent and severe malaria by 49 percent.

Aba Baffoe-Wilmot, the deputy head of Ghana's Malaria Control Program, says if the vaccine proves successful, it will be a major victory in the fight against malaria.

"In the past, there had been vaccines, which have been tried in Colombia, Tanzania and elsewhere in the world, and really nothing came out of it," she said. "So, this time, if this coming out, and it proves to be effective and efficient, hurray, we are [will be] very happy."

Malaria thrives in hot temperatures, which enable the parasite that causes the disease to mature more quickly in the bodies of the mosquitoes that carry it. Over the years, the parasite carried by the mosquito has become more resistant to known medications, and new drugs have been tried to combat the disease.

But, this program's vaccine has been tested and proved successful in protecting a large group of people - adult volunteers in the United States, Europe, The Gambia and Kenya, as well as children in Gambia and Mozambique.

Now, researchers from the U.S. Walter Reed Army Institute of Research, GlaxoSmithKline Biologicals, and the British Medical Research Council are testing 540 children in Ghana between five and 17 months.

Baffoe-Wilmot of Ghana's malaria control program says the vaccine cannot and should not substitute for preventive measures, such as proper hygiene and sleeping under treated mosquito nets. And, she says, people need to be educated.

"And when you look at our lifestyles, our behavior, we really encourage the breeding of these mosquitoes. So, if we can really pay some great attention, changing the behavior of people, letting them know that it is this mosquito, which is doing it, and we [are] combating it and controlling it, at least we will get somewhere," she said. "It is a great challenge."

The vaccine is also being tested in Kenya, Sierra Leone, Gabon, Tanzania and Senegal. The researchers say, if successful, it would be in use by 2011.

Various international and national institutions, including Data Safety Monitoring Board in the United States and the London School of Ethics, are supervising the trials.