Bill Gates's World of Possibility

Melinda Moree met plenty of naysayers who dismissed the prospects of a malaria vaccine. Then she encountered Bill Gates.

No one had developed a human vaccine against a parasite like malaria before, and the monetary incentives simply did not exist for pharmaceutical companies to develop drugs targeted at poor children. Development would require cooperation among scientists, drug companies, health groups and international governments -- an alliance so large it didn't seem possible, she recalled someone telling Gates.

Of course it is, Gates countered, according to Moree, now director of the PATH Malaria Vaccine Initiative in Seattle, which along with other groups has received nearly $500 million from the Bill and Melinda Gates Foundation to develop, test, manufacture and eventually distribute a malarial vaccine. There's something about vision and belief that these things are possible, Moree said.

People in the nonprofit world say Gates, 50, could fundamentally alter the methodology of philanthropy with his announcement last week that he will quit his day-to-day role at Microsoft Corp. in two years to spend more time on his foundation. He will take the same energy he once directed toward software technology to global health, education and other intractable issues, they say.