In the early 20th century, polio was, as the World Health Organisation’s Global Polio Eradication Initiative notes, one of the most feared diseases in industrialised countries, paralysing hundreds of thousands of children every year.
However, soon after the introduction of effective vaccines in the 1950s and ’60s it “was brought under control and practically eliminated as a public health problem in these countries”.
The person credited with this achievement is Jonas Salk, a medical doctor and virologist born in New York City on 28 October 1914.
Poliomyelitis is caused and transmitted by the poliovirus. As an article published by Oxford University’s Oxford Martin research school explains, the name is derived from Greek and translates to grey (polios) marrow (myelon), “which refers to the tissue in the centre of the spinal cord, which when affected causes paralysis”.
“Paralysed limbs such as arms or legs waste away over time, which is the cause of deformed child legs most commonly being associated with the disease polio.”
In many ways, the ultimate success of Salk’s vaccine is attributable to a national effort that seems unlikely in the US today.
In 1921, Franklin D Roosevelt, then 39, was diagnosed with polio (though this has since been disputed). Seventeen years later, as US president, he established the National Foundation for Infantile Paralysis (NFIP) to combat the disease.
Salk, meanwhile, was earning a medical degree from the New York University School of Medicine. He graduated in 1939, but rather than practise medicine he became a researcher at New York’s renowned Mount Sinai Hospital.
In 1942 he moved to the University of Michigan on a research fellowship to work on developing an influenza vaccine, eventually becoming an assistant professor of epidemiology.
By then, Roosevelt’s NFIP was known as the March of Dimes and had mass appeal as a grassroots fund-raising program; reportedly two-thirds of the US population gave money. The New York Times says that by the late 1940s the organisation was raising about $US50 million a year.
So, in 1947, when Salk became director of the virus research laboratory at the University of Pittsburgh School of Medicine, in Pennsylvania, he was well supported in his directed task to come up with a polio vaccine.
A report by the Public Broadcasting Service says Salk used formaldehyde to kill the polio virus but keep it intact enough to trigger the body’s response.
On 2 July 1952, he tried a refined vaccine on children who’d already had polio and recovered. “After the vaccination, their antibodies increased. He then tried it on volunteers who had not had polio, including himself, his wife, and their children. The volunteers all produced antibodies, and none got sick.”
“In scientific terms,” says an online article in the University of Pittsburgh’s Pittwire, “the team demonstrated that chemically inactivated polioviruses could be used successfully to create a vaccine. This gave researchers a broader set of tools to work with for creating vaccines against viral illnesses. And while the team’s virus was not the first killed-virus vaccine, it did smash conventional notions of how vaccines were supposed to be made. Up to that point, scientific consensus was only weakened versions of live viruses could produce lasting protective immunity.”
In 1954, national testing began on almost a million children, aged six to nine, who became known as the Polio Pioneers, the March of Dimes reports.
On 12 April 1955, the Salk vaccine was licensed for use, announced in the media as being “safe, effective, and potent”. Shortly afterwards, Albert Sabin introduced a live polio vaccine that could be administered orally, rather than Salk’s by injection.
In 1963 Salk founded the Salk Institute for Biological Studies, in La Jolla, California. He spent his last years searching for a vaccine against AIDS.
He died in La Jolla on 23 June 1995.
Jeff Glorfeld is a former senior editor of The Age newspaper in Australia, and is now a freelance journalist based in California, US.
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