Pushing Back Polio
50 years ago this week, daring scientists beat a germ that was crippling the nation
It was a Tuesday in Mapleton, Iowa, when 16-year-old Catherine Thiel got sick on her family's farm. The year was 1952, a sweltering July. At first it was just a fever, but Catherine soon worsened and got a dread diagnosis: polio. Catherine's brother Jerry fell ill later that week, followed by their sister, followed by another and another until 11 of the 14 Thiel kids were stricken. Two were left paralyzed.
The Thiels were far from alone. That year was the worst polio outbreak on record with some 57,000 cases, 21,000 of whom were paralyzed and 3,000 of whom died. The country had been struggling with this virus since 1916; the disease had no cure, and there was no way to prevent it. "Parents were scared," says Julius Youngner, who in 1952 was a young father of two living in Pittsburgh. "When I was growing up, we would see kids with shriveled legs and crutches. And I wanted to protect my own kids." Unlike other parents, though, Youngner could do something for his children and many more. He was working with Jonas Salk at the University of Pittsburgh on a polio vaccine. They moved fast, going from test tubes to tests on children in a scant three years--a speed that would be impossible with today's medical bureaucracy, says Youngner, now 84 and the last surviving member of Salk's team.
Shortcuts. It worked: Fifty years ago this week, the researchers announced to the world that the vaccine had prevented polio in a trial of 1.8 million children and would be immediately used on the general public. It was "the largest public-health experiment in American history," notes historian David Oshinsky in his new book, Polio: An American Story, and it helped banish polio from the United States. But the urgency of the project also involved some ethical shortcuts, and set the stage for one medical disaster.
Most scientists, in the 1950s, actually thought the shots wouldn't work at all, because Salk's vaccine used a killed version of the polio virus. The basic idea of a vaccine is to prompt the body to develop immunity to the virus, and many doubted that a dead virus was threatening enough to awaken the body's defenses. Researchers thought a vaccine using a live but badly weakened virus, of the type eventually produced by Albert Sabin, would be a better bet.
But Salk and his colleagues had one thing that Sabin didn't have: data. Youngner had developed ways to grow lots of virus, so Salk's team was able to compare many different preparations. Between 1951 and 1952, the team identified the three most common varieties of the virus and developed a way to chemically kill them that still left the virus intact enough to provoke an immune response in monkeys.
The next step was humans. "I know we were moving at what would now be considered warp speed," says Youngner. "But we were motivated. Our labs were on the first floor of what was then called Municipal Hospital, and on the third floor was a ward of iron lungs. Polio was all around us."
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