Polio vaccine turns 70 as politics fuel hesitancy
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Jonas Salk and nurses administer a polio vaccine in Pittsburgh in 1955. Photo: Bettmann Archive/Getty Images
Jonas Salk's polio vaccine, developed in Pittsburgh, was declared safe and effective 70 years ago this week.
Why it matters: Polio was once among the world's most feared diseases, annually immobilizing or killing hundreds of thousands of people, mainly children. In the U.S. alone, over 58,000 cases were reported in 1952.
- Now, Pittsburghers can explore Salk's legacy at the University of Pittsburgh School of Public Health and Heinz History Center exhibits.
Zoom in: Salk and his team at the University of Pittsburgh spent seven years developing the vaccine, first testing it on Pittsburgh-area children, then on 1.8 million across North America in what became one of the largest clinical trials in history.
- On April 12, 1955, Salk's mentor Thomas Francis announced to the world that the vaccine was "safe, effective, and potent," bringing a wave of global relief.
- Polio cases in the U.S. dropped by about 90% within two years, NPR reported — securing the city's role as a leader in public health research.
The intrigue: Anti-vaccine sentiments have since become tied to conservative political identity, contributing to a decline in childhood vaccination rates and a rise in vaccine hesitancy.
Context: Childhood vaccination rates have dropped in recent years nationally and in Pennsylvania.
- Kindergarten rates for polio, MMR and other vaccines hovered below 95% during the 2023-24 school year, per Pennsylvania Department of Health data.
The latest: Health and Human Services Secretary Robert F. Kennedy Jr. has falsely claimed the polio vaccine did not actually result in a drastic decline in infections.
- He also claimed the vaccine may have caused cancers that killed more people than polio did because of some early contaminated doses. Most studies have shown no connection between those early shots and cancer, and researchers have been unable to replicate the one study that did, the AP reported.
Caveat: Kennedy has since vowed not to withdraw the polio vaccine's approval, even though one of his campaign operatives has petitioned the FDA to revoke it.