First Malaria vaccine to be tested in three African nations

Johannesburg, South Africa — Three African countries have been chosen to test the world's first malaria vaccine, the World Health Organization announced Monday.

Ghana, Kenya and Malawi will begin piloting the injectable vaccine next year with hundreds of thousands of young children, who have been at highest risk of death.

The vaccine, which has partial effectiveness, has the potential to save tens of thousands of lives if used with existing measures, the WHO regional director for Africa, Dr. Matshidiso Moeti, said in a statement.

The challenge is whether impoverished countries can deliver the required four doses of the vaccine for each child. Malaria remains one of the world's most stubborn health challenges, infecting more than 200 million people every year and killing about half a million, most of them children in Africa. Bed netting and insecticides are the chief protection.

Sub-Saharan Africa is hardest hit by the disease, with about 90 percent of the world's cases in 2015.

Malaria spreads when a mosquito bites someone already infected, sucks up blood and parasites, and then bites another person.

A global effort to counter malaria has led to a 62 percent cut in deaths between 2000 and 2015, WHO said.

But the U.N. agency has said in the past that such estimates are based mostly on modeling and that data is so bad for 31 countries in Africa - including those believed to have the worst outbreaks - that it couldn't tell if cases have been rising or falling in the last 15 years.