Bill Gates thinks the world has finally won the war on polio.
His foundation has been a major player in battling polio. Years later, only 12 documented cases of the paralyzing virus exist in Afghanistan and Pakistan. Only 30 years ago, polio was in more than 125 countries, afflicting 350,000 people annually.
A global mass immunization effort was launched in 1988. More than 2.5 billion children were orally vaccinated, saving an estimated 13 million. But declaring absolute victory is dangerous. Measles, mumps, and whooping cough are making comebacks in the U.S., partially because of the anti-vaccine movement. About 1 in 10 American parents delay or refuse to vaccinate their children, leaving the door open to diseases meant for history.