• MGMUS

Poliovirus and the Years-Long Development of a Vaccine




The poliovirus is one of the most ancient of the viruses that affect humans, disabling people in even the earliest civilizations. Egyptians left behind images of people bearing the debilitated limbs characteristic of polio, the disease poliovirus causes, and children using canes to walk. In 1789, when modern medicine was still young, English physician Michael Underwood wrote the first description of the symptoms of the virus, and for nearly two centuries more, children and adults continued to suffer the horrendous effects. It affected paupers and presidents alike, putting FDR in a wheelchair and in 1952 (the worst poliovirus epidemic in US history) leaving more than 21,200 permanently disabled.

In the 1930s, researchers Maurice Brodie and John Kolmer, of New York University and Temple University respectively, conducted the first polio vaccine trials in earnest. They reported success inoculating monkeys from poliovirus in early 1935 and proceeded to trials in human subjects, encountering much more turbulent results. When several children died during their trials, the American Public Health Association reacted with outrage. They put an end to the trials – which remained the most promising for more than a decade and a half. For seventeen years after that, research developed more slowly because studies remained confined to laboratories. The most significant breakthrough was John Enders's cultivation of poliovirus, in 1948, at Children's Hospital Boston.

As Americans reeled from the record- setting number of poliovirus cases in 1952, citizens hurting and frightened clamored for a safe and effective vaccine. Several teams studied potential vaccines independently, and out of them, it was Jonas Salk and his team at the University of Pittsburgh that reported the most promising results: successful inoculation in a group that included both adults and children. That was March 1953, and in February 1954, Dr. Salk expanded his tests, to Arsenal Elementary School and the Watson Home for Children, both in Pittsburgh. From there, he expanded again, to a trial of 4,000 children, and then once again to 1.8 million in 44 different states.

On April 12th, 1955, the 10-year anniversary of the death of President Franklin D. Roosevelt, who had himself contracted poliovirus and experienced its debilitating effects, Dr. Salk announced that his vaccine was effective. The response in the news media was ecstatic, word of the vaccine dominating radio broadcasts and newspapers, triumphal headlines proclaiming, "SALK'S VACCINE WORKS!" and "POLIO ROUTED!". Dr. Salk became an overnight celebrity. To Houston, New York, Louisville, and other cities that poliovirus had battered, boxes started to arrive like miracles, marked in bold letters "POLIO VACCINE RUSH."

In households where anxiety about poliovirus had festered, there was relief. Americans who had feared for the worst – sick children, paralyzed children, dying children – were able to breathe more easily, all thanks to their new national hero. In the months that followed, there was a nationwide campaign to vaccinate American children, promoted largely by President Roosevelt's foundation the March of Dimes. Within six years, the number of poliovirus cases in the US had plummeted to 161, down from the all-time high of 57,628 in 1952.



Throughout the 90s and the 2000s, countries worldwide eradicated poliovirus through concerted, large-scale vaccination programs. India, which had experienced sporadic outbreaks throughout the 2000s, declared itself polio-free in March 2014. Today there are just two countries where poliovirus occurs: Afghanistan and Pakistan.

While the development of the poliovirus vaccine stretched over multiple decades, the development of the coronavirus vaccine has already shown substantial promise a year since the Chinese government reported the first cases in the province of Wuhan. As of November 23rd, pharmaceutical firms Pfizer and Moderna have both announced impressive efficacy rates in their vaccine trials, while Johnson & Johnson and AstraZeneca have pushed forward with trials as well – a credit to modern science, hardworking researchers, and pioneers like Jonas Salk who laid the framework for modern immunology. The pandemic continues, but hope for us, unlike Americans in 1952, seems months and not years in the offing.