Skip to Main Content
Whatever Happened to Polio? home page
Subsections for the Virus and Vaccine are A Living ChemicalHow the Poliovirus WorksThe Polio Genome History of VaccinesTwo VacccinesClinical TrialsMedical Philanthropy
Secondary sections of the site are ActivitiesTimelineHistorical PhotosResourcesVisitor Info
The Virus and Vaccine, The Vaccines Races

Quote.I have just figured out that during the coming summer, thirty or forty thousand children will get polio. About fifteen thousand of them will be paralyzed and more than a thousand will die. If we have the capacity to prevent this, we have a social responsibility Ö we are supported by the people and it is our duty to save lives no matter how many difficulties may be involved. -Basil OíConnor, president of March of Dimes, 1954

From the early 1900s, researchers pursued two different kinds of polio vaccine. One used inactivated (killed) viruses. The other kind used live but attenuated, or weakened, virus. Jonas Salk was the leading proponent of the killed virus and Albert Sabin became the foremost proponent of the attenuated virus approach.
Factoids
bullet At its peak incidence in the early 1950s, poliomyelitis occurred at a rate of 13.6 cases per 100,000 population. The incidence of cancer today, by comparison is 566.1 per 100,000.
bullet Edward Jenner created the first successful vaccination for a disease—smallpox—in 1796. At the time of the polio clinical trials, there were three widely used vaccines: for yellow fever (1937), rabies (1885), and smallpox. Today there are over 300 vaccines for about thirty different diseases.
bullet There are two kinds of polio vaccine. IPV (Salk’s) is an injected shot used today primarily in the United States and Europe. OPV (Sabin’s) is given orally in drop form and used in global efforts to stop polio transmission.
Albert Sabin, Jonas Salk, and Basil O'Connor standing next to each other
Albert Sabin (left) and Jonas Salk (center) meeting with Basil O’Connor of the March of Dimes in 1961 Courtesy of March of Dimes

The Salk Vaccine
The chief advantage of Salk’s killed virus vaccine was safety. If made properly, it could not cause disease. Its chief disadvantage was that the formaldehyde used in its manufacture caused the immune system to recognize killed virus differently from live virus, possibly risking a shortened period of immunity.

Results of trials with small numbers of children in 1952 encouraged the National Foundation for Infantile Paralysis to adopt Salk’s vaccine for a large-scale trial in 1954. Salk called his vaccine “Pittsburgh vaccine,” but reporters named it “Salk.”
Left photo. Vaccine bottles and syringe
Enlarge Image
Right photo. Salk standing in his lab
Left: Vaccine bottles and 5-cc syringe used by Jonas Salk in the 1954ñ55 clinical trials
Right: Jonas Salk in his lab at the University of Pittsburgh, 1954 Courtesy of March of Dimes
Black children and white children standing in segregated lines in a yard in front of a building
Some of the thousands of children who received free vaccine in the weeks following the announcement, waiting in segregated lines Courtesy of Memphis Commercial Appeal
Photo of a formaldehyde bottle with a label reading E and A Tested for Purity Reagent

Formaldehyde from Jonas Salkís laboratory. At the University of Pittsburgh in 1952, Salk used formaldehyde to inactivate poliovirus. Formaldehyde chemically freezes the virus, effectively stopping its reproduction.

Time magazine cover with an illustration of Salk, leg braces, crutches, and syringes
Enlarge Image

Jonas Salk on the cover of Time magazine.

Explore this Topic (popup window)
Listen to a Story (popup window)
    Jonas Salk, 1990  
page 1, 2
Smithsonian National Museum of American History main site
SMALL TEXT
LARGE TEXT