Today in History—April 12: The Press Conference That Ended Polio

A man in a lab coat and glasses, identified as Jonas Salk, handles a rack of test tubes at a press conference related to the polio vaccine, with laboratory equipment visible in the foreground. — April 12, 1955: The day polio met its match

On this day in 1955, Thomas Francis, Jr., director of the Poliomyelitis Vaccine Evaluation Center at the University of Michigan School of Public Health, spoke to a packed auditorium—scientists, doctors, reporters—and distilled a 113-page report down to three important words: safe, effective, potent.

Polio, then the most feared disease in the world, had met its match in a vaccine developed by physician and researcher Jonas Salk.

Celebrations erupted. People wept in the streets. Churches rang bells, factories blew whistles, and parents hardly dared believe the news.

Known for millennia and first described clinically in 1789, polio was insidious, often striking children. By 1950 half a million people worldwide were afflicted each year. Survivors often faced lifelong consequences, from limb deformities to respiratory paralysis that required the use of the much-maligned iron lung ventilator—where some had to remain for years.

Salk and his team worked out of a basement at the University of Pittsburgh, sandwiched between a morgue and a darkroom. They got their virus samples directly from the poop of patients on the third floor. In just four years the team had developed a vaccine that Salk took home to administer to his wife and sons, boiling needles in their kitchen to sterilize them.

The press conference summarized the results of a two-year trial involving nearly two million children. Nothing of that scale had ever been attempted in modern medicine. The vaccine proved 80–90 percent effective in preventing disease and greatly lessened the severity of disease in those who did contract it. No inoculated children died.

Francis smiled as he spoke, shoulder to shoulder with Salk.

Jonas Salk, after all, had been his student.

Fun Fact

U.S. Pres. Franklin D. Roosevelt, who contracted polio at age 39, founded the March of Dimes, the charity that would eventually fund Salk’s vaccine work.

The vaccine was licensed that same day. Production began immediately. Within a few years the number of cases in the United States fell from tens of thousands to hundreds.

Salk never patented the vaccine. When a reporter asked him who owned it, Salk replied, “Could you patent the Sun?”

His vaccine conferred protection, but it didn’t stop transmission. That came later, with the oral polio vaccine, developed on the heels of Salk’s injectable one.

Today, polio is on the ropes, down 99 percent worldwide since that press conference, with outbreaks confined to a handful of countries and eradication efforts continuing.

Neither of the two vaccines was ever patented.