This is an I-Heart podcast.

Guaranteed Human.

Welcome to Nuts World Podcast on the IHeart Podcast Network, the greatest American inventions.

Today, we're not talking about a device or a network or a machine.

We're talking about a needle and the liquid it contained,

and the millions of children who held out their arms and were saved, the polio vaccine.

If you were born after 1960, you'd probably never known anyone who had polio.

That absence is itself the measure of this invention's success.

But if you were born before 1955, you almost certainly remember what summers were like when polio was real.

Swimming pools closed, movie theaters emptied. Parents kept

children indoors. The iron lung, a metal cylinder that breathed for you when the virus had

paralyzed your respiratory muscles, was a fixture of hospital wards. In 1952, the worst outbreak in American history, nearly 58,000 cases, 3,000 dead,

more than 21,000 paralyzed. Jonas Salk would not accept this. Working at the University of Pittsburgh,

he pursued with the scientific establishment

considered the wrong approach. A killed virus vaccine using an activated poliovirus that could not cause

disease, but would still trigger an immune response. The leading researchers of the day

believed only a live, weakened virus could produce

lasting immunity. Salk disagreed, and he was right. His approach was methodical and meticulous,

identifying which strains were circulating, finding ways to grow the virus in sufficient quantities,

killing it reliably without destroying its ability to provoke immunity.

By 1953, he was confident enough to inoculate himself and his own family.

In 1953, and his own family. In 1954, the largest clinical trial in American history,

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