In 1980, the eradication of smallpox captured the world's imagination. After a massive, 20-year campaign, the world had, for the first time, completely wiped out a disease. Buoyed by this victory, several organizations looked to the next likely candidate for eradication: polio. Most industrialized countries had already conquered polio with vaccines developed in the 1950s. But wild poliovirus continued to thrive in 125 poorer countries, permanently disabling more than 500,000 people every year.

This section tells the story of how, less than a generation later, the number of new cases of polio in the world has plummeted to fewer than 500. It describes the disease, the race to invent a vaccine and the international coalition that has planned, financed and implemented this huge effort. It traces the carefully orchestrated strategies forged to overcome vast challenges and deliver several drops of polio vaccine to, at the peak, 550 million children a year. And it explains why millions of individuals have come together to bring the world within reach of eradication.

© Sebastião Salgado

Democratic Republic of Congo

A day before a mass immunization campaign against polio begins, health workers transport vaccine and other supplies to remote communities, along a jungle road near the eastern city of Kisangani. The vaccine cold-storage boxes bear the continent-wide campaign slogan 'Kick polio out of Africa'.