Microsoft founder and former CEO Bill Gates has been spending his retirement—and the billions of dollars he’s amassed over the years—to try to improve the education system here in the U.S. and wipe out polio worldwide.
During an appearance on The Daily Show last night, Gates talked about the challenges of administering polio vaccinations in India, Nigeria, Pakistan and Afghanistan—the four remaining places in the world where the disease is still a big problem. Check out video of the interview above.
“As long as we don’t get rid of it there,” said Gates, “It kind of spreads out. We tamp it down but those are the four where we’ve never gotten it to zero. But we’re optimistic in the next few years that we’ll get it done.”