Melinda Gates and Susan Desmond-Hellmann

For the past 15 years, the Gates Foundation has leveraged its $44.3 billion endowment to attempt to eradicate diseases like malaria in the developing world. Under new CEO Desmond-­Hellmann, a former Genentech product chief, the foundation could become an even bigger player in global health. Last year the foundation financed a prototype of a plant that converts human feces into drinkable water; meanwhile, a $1.5 billion commitment to vaccination organization Gavi will ensure that an additional 300 million children will be vaccinated by 2020.