The Man who Stopped Polio

By Laura Boness

Imagine not being able to play with friends or go to the local swimming pool on a hot day because of a highly infectious disease that could kill you or leave you paralysed? If it weren’t for Jonas Salk, that would be the case.

Poliomyelitis,or polio, once infected thousands of people throughout the world and while many didn’t have any symptoms, it caused death or paralysis. The first outbreak was recorded in the 19th century and the disease slowly became more common until a scientist named Jonas Salk found a way to stop it in its tracks.

Born in 1914 in New York, he was the first member of his family to go to university, originally intending to become a lawyer. However, he put aside these plans and went to medical school and, instead of becoming a practicing physician, Salk took a year off to study biochemistry, becoming a medical researcher.

After graduation, he was invited to study the influenza virus and work on a vaccine in a project funded by the US army. This research not only led to the creation of a flu vaccine, it later formed the basis of his work when he was asked to work on polio.

Polio epidemics had continued through the first half of the 20th century and were growing worse. In 1952 the US recorded nearly 58,000 cases with 3,145 people dying and 21,269 left with mild to disabling paralysis. A year earlier, Salk had discovered that there were three types of polio and had also managed to create a ‘killed’ virus, using samples that had been grown in the laboratory and then killed with formaldehyde.

The principle of vaccination is that if our bodies are exposed to a harmless form of a disease virus, they will produce antibodies that kill or resist the dangerous form of the virus if we are exposed to it later in life. When he worked on the influenza virus, Salk realised that inactivated (killed), noninfectious viruses could also be used to produce these antibodies. So when he killed the virus, he kept it intact enough to trigger this immune response.

The vaccination was tested on monkeys, then on people who already had polio. The next people to receive it were volunteers who hadn’t been infected, including Salk, his laboratory staff, his wife and their children. None of them had an adverse reaction and national testing began in 1954, with one million Polio Pioneers (children aged six to nine) receiving either the vaccine or a placebo.

When the vaccine was approved for general use in 1955, the entire nation celebrated and Salk became a hero. Instead of taking the chance to make a fortune from his work, he refused to patent his vaccine – he wanted to see it distributed as widely as possible. He spent time refining the vaccine and the scientific principles behind its creation before he moved on to other studies.

In 1962, a second polio vaccine was licensed, this time by a scientist named Albert Sabin. This vaccine uses the live virus instead of the ‘killed’ virus and mostly replaced Salk’s vaccine between 1963 and 1999 because it was cheaper and easier to administer. However, there were concerns that the live virus can become strong enough to cause the actual disease, therefore Salk’s version is the one now used in Australia and the US.

Meanwhile, the Australian researchers established the Salk Institute for Biological Studies in 1963, where he and other scientists studied diseases such as cancer and multiple sclerosis. He later went on to examine HIV and AIDS before his death in 1995. His institute now contains labs where scientists study a variety of topics, from AIDS, Parkinson’s and Alzheimer’s to cancer, diabetes and even plant biology. Polio, which once struck almost every year, has now largely been eradicated, although efforts to wipe out polio still continue in some countries around the world.