Polio is an infectious disease that affects children in particularly terrible ways. Once the poliovirus invades the nervous system, it can cause irreversible paralysis in a matter of hours. As a consequence, many affected children suffered from permanent disability of the muscles in their legs. In the worst cases, it affects the muscles a child uses to breathe, which means that the child suffocates and dies.

To prevent them from dying of suffocation, polio victims were once placed into large mechanical breathing apparatuses called iron lungs. The iron lung was both a lifeline and a life sentence for those permanently paralyzed by the virus, as they would have to remain inside the metal box for years.

Children are still suffering from polio today, but the disease is much rarer than it once was. In this short article, I want to show how far the world has come in our battle against polio, and I want to show that we today have the opportunity to end polio once and for all. This — the global eradication of polio — would surely rank among humanity’s greatest achievements.

As recently as the 1980s, hundreds of thousands of people worldwide became paralyzed by the virus every year. Since then, the efforts against polio have been successful in more and more regions of the world, and the spread of the virus has been contained greatly, as the chart shows.

This global reduction of paralytic polio cases is only part of the success. There were previously three different serotypes of wild poliovirus, and immunity to one serotype does not confer immunity to the other two. Two of them were eradicated in the last decade:

  • The last case of wild poliovirus serotype 2 was seen in 1999 in India. It was declared globally eradicated by the WHO in 2015.
  • The last case of wild poliovirus serotype 3 was seen in 2012 in Nigeria and declared eradicated in 2019.

The maps below the chart show how polio was eliminated in more and more countries. Back in 1980, polio was still endemic in 147 countries around the world. By 2000, North and South America were certified to be polio-free. Twenty years later, most regions in the world are certified to be free of polio.

A global vaccination campaign made this success possible

The chart shows how this was possible. Back in 1980, only 1 out of 5 of the world’s infants got vaccinated. By now, that ratio has flipped, and 1 out of 5 are not vaccinated.

Read the full article about the fight against polio by Max Roser at Our World in Data.