Bill Gates administers polio drops to a child during a ceremony hosted by Chadian President Idriss Déby to launch a three-day nation-wide polio campaign that aimed to reach 2.2 million children under five. (N'Djamena, Chad, 2011)
Today Bill Gates will be delivering the annual Dimbleby Lecture in the U.K. on why he is committed to eradicating polio.
