1956: Dr. Albert Sabin announces that his live-virus oral polio vaccine is ready for mass testing. It will soon supplant the Salk vaccine.

Poliomyelitis is an infectious disease caused by viruses. Its effects range from complete recovery to death. Intermediate possibilities are mild after-effects, moderate to severe paralysis of a limb or limbs, or paralyzed chest muscles, necessitating the confining but lifesaving use of an iron lung.

Polio epidemics periodically ravaged American cities in the first half of the 20th century. Children were especially vulnerable, but the disease also struck adults, most notably former Assistant Secretary of the Navy Franklin D. Roosevelt in 1921.

Roosevelt was elected president in 1932, and he founded the National Foundation for Infantile Paralysis (as the disease was then often called) in 1938. The foundation conducted a huge annual fundraising campaign called the March of Dimes.

The polio epidemics of the early 1950s terrified American parents and their children. Between 1950 and 1952, the number of severe or fatal U.S. cases doubled to 55,000.

Authorities closed swimming pools during the warm months when new polio infections peaked. Parents kept kids at home instead of exposing them to possible contagion at summer camps. If you didn’t know someone who had been stricken (though most recovered), you knew about a kid at your cousin’s school, or the cousin of some kid at your school.

So, America breathed a sigh of relief — and millions lined up for their shots to prevent the dread disease — after Dr. Jonas Salk announced in 1955 (on the 10th anniversary of President Roosevelt’s death) that a dead-virus injected vaccine had been proven safe and effective.

Sort of effective: You needed a booster shot every three years or so.

Sort of safe: A live virus could occasionally find its way into the vaccine, and one batch in 1955 infected 44 children with polio within days of getting the inoculations that were supposed to prevent the disease.

Sabin’s 1956 announcement of an new type of polio vaccine provided hope of an alternative. But most Americans believed the only good virus was a dead virus. Sabin wound up doing most of his large-population tests on Soviet schoolchildren.

It was safer. It was more effective, conferring immunity that might last a lifetime. And it was also easier for kids to take — by mouth, in a cherry-flavored sugar cube.

The Sabin vaccine was adopted as the standard by 1961, the Salk vaccine remembered mainly as a historically important stopgap.

Polio survivors of the pre-vaccine years must be on guard, however, against the debilitating effects of post-polio syndrome: muscle weakening that can develop decades after infection. But, thanks to nearly universal immunization, polio is now largely unknown in the United States, and
global polio eradication is one of the goals of the Bill & Melinda Gates Foundation.

Source: High Beam Encyclopedia

Photo: Dr. Albert Sabin, of the University of Cincinnati College of Medicine, holds a vial containing the newly developed oral polio vaccine. (Bettmann/Corbis)

This article first appeared on Wired.com Oct. 6, 2008.