A major study of the world's first malaria vaccine is underway in Africa – starting with Malawi followed by Kenya and Ghana.
The disease spread by mosquitos kills over 400,000 people each year, most of them young children.
Almost 1 billion. The dollar has gone into developing the vaccine over three decades.
Initial testing of the RTS world's first anti-malaria vaccine has shown that it reduces cases by approx. 40%.
Video producer: Rupert Waring for focus on Africa TV.