How thousands of first- and second-graders saved the world from a deadly disease
Although Jonas Salk has gone down in history for helping rid the world (almost) of polio, his revolutionary vaccine wouldn't have been possible without the world’s largest clinical trial – and the bravery of thousands of kids.
Exactly 67 years ago, in 1955, a group of scientists and reporters gathered at the University of Michigan and waited with bated breath for Dr. Thomas Francis Jr., director of the school’s Poliomyelitis Vaccine Evaluation Center, to approach the podium. The group had gathered to hear the news that seemingly everyone in the country had been anticipating for the past two years – whether the vaccine for poliomyelitis, developed by Francis’s former student Jonas Salk, was effective in preventing the disease.
Polio, at that point, had become a household name. As the highly contagious virus swept through the United States, cities closed their schools, movie theaters, swimming pools, and even churches to stop the spread. For most, polio presented as a mild illness, and was usually completely asymptomatic – but for an unlucky few, the virus took hold of the central nervous system and caused permanent paralysis of muscles in the legs, arms, and even people’s diaphragms, rendering the person unable to walk and breathe. It wasn’t uncommon to hear reports of people – mostly children – who fell sick with a flu-like virus and then, just days later, were relegated to spend the rest of their lives in an iron lung.
For two years, researchers had been testing a vaccine that would hopefully be able to stop the spread of the virus and prevent the 45,000 infections each year that were keeping the nation in a chokehold. At the podium, Francis greeted the crowd and then proceeded to change the course of human history: The vaccine, he reported, was “safe, effective, and potent.” Widespread vaccination could begin in just a few weeks. The nightmare was over.
The road to success
Jonas Salk, a medical researcher and virologist who developed the vaccine with his own research team, would rightfully go down in history as the man who eradicated polio. (Today, wild poliovirus circulates in just two countries, Afghanistan and Pakistan – with only 140 cases reported in 2020.) But many people today forget that the widespread vaccination campaign that effectively ended wild polio across the globe would have never been possible without the human clinical trials that preceded it.
As with the COVID-19 vaccine, skepticism and misinformation around the polio vaccine abounded. But even more pervasive than the skepticism was fear. The consequences of polio had arguably never been more visible.
The road to human clinical trials – and the resulting vaccine – was a long one. In 1938, President Franklin Delano Roosevelt launched the National Foundation for Infantile Paralysis in order to raise funding for research and development of a polio vaccine. (Today, we know this organization as the March of Dimes.) A polio survivor himself, Roosevelt elevated awareness and prevention into the national spotlight, even more so than it had been previously. Raising funds for a safe and effective polio vaccine became a cornerstone of his presidency – and the funds raked in by his foundation went primarily to Salk to fund his research.
The Trials Begin
Salk’s vaccine, which included an inactivated (killed) polio virus, was promising – but now the researchers needed test subjects to make global vaccination a possibility. Because the aim of the vaccine was to prevent paralytic polio, researchers decided that they had to test the vaccine in the population that was most vulnerable to paralysis – young children. And, because the rate of paralysis was so low even among children, the team required many children to collect enough data. Francis, who led the trial to evaluate Salk’s vaccine, began the process of recruiting more than one million school-aged children between the ages of six and nine in 272 counties that had the highest incidence of the disease. The participants were nicknamed the “Polio Pioneers.”
Double-blind, placebo-based trials were considered the “gold standard” of epidemiological research back in Francis's day - and they remain the best approach we have today. These rigorous scientific studies are designed with two participant groups in mind. One group, called the test group, receives the experimental treatment (such as a vaccine); the other group, called the control, receives an inactive treatment known as a placebo. The researchers then compare the effects of the active treatment against the effects of the placebo, and every researcher is “blinded” as to which participants receive what treatment. That way, the results aren’t tainted by any possible biases.
But the study was controversial in that only some of the individual field trials at the county and state levels had a placebo group. Researchers described this as a “calculated risk,” meaning that while there were risks involved in giving the vaccine to a large number of children, the bigger risk was the potential paralysis or death that could come with being infected by polio. In all, just 200,000 children across the US received a placebo treatment, while an additional 725,000 children acted as observational controls – in other words, researchers monitored them for signs of infection, but did not give them any treatment.
As with the COVID-19 vaccine, skepticism and misinformation around the polio vaccine abounded. But even more pervasive than the skepticism was fear. President Roosevelt, who had made many public and televised appearances in a wheelchair, served as a perpetual reminder of the consequences of polio, as an infection at age 39 had rendered him permanently unable to walk. The consequences of polio had arguably never been more visible, and parents signed up their children in droves to participate in the study and offer them protection.
The Polio Pioneer Legacy
In a little less than a year, roughly half a million children received a dose of Salk’s polio vaccine. While plenty of children were hesitant to get the shot, many former participants still remember the fear surrounding the disease. One former participant, a Polio Pioneer named Debbie LaCrosse, writes of her experience: “There was no discussion, no listing of pros and cons. No amount of concern over possible side effects or other unknowns associated with a new vaccine could compare to the terrifying threat of polio.” For their participation, each kid received a certificate – and sometimes a pin – with the words “Polio Pioneer” emblazoned across the front.
When Francis announced the results of the trial on April 12, 1955, people did more than just breathe a sigh of relief – they openly celebrated, ringing church bells and flooding into the streets to embrace. Salk, who had become the face of the vaccine at that point, was instantly hailed as a national hero – and teachers around the country had their students to write him ‘thank you’ notes for his years of diligent work.
But while Salk went on to win national acclaim – even accepting the Presidential Medal of Freedom for his work on the polio vaccine in 1977 – his success was due in no small part to the children (and their parents) who took a risk in order to advance medical science. And that risk paid off: By the early 1960s, the yearly cases of polio in the United States had gone down to just 910. Where before the vaccine polio had caused around 15,000 cases of paralysis each year, only ten cases of paralysis were recorded in the entire country throughout the 1970s. And in 1979, the virus that once shuttered entire towns was declared officially eradicated in this country. Thanks to the efforts of these brave pioneers, the nation – along with the majority of the world – remains free of polio even today.
Scientific breakthroughs offer our only solution for a safe return to normal life.
Kira Peikoff was the editor-in-chief of Leaps.org from 2017 to 2021. As a journalist, her work has appeared in The New York Times, Newsweek, Nautilus, Popular Mechanics, The New York Academy of Sciences, and other outlets. She is also the author of four suspense novels that explore controversial issues arising from scientific innovation: Living Proof, No Time to Die, Die Again Tomorrow, and Mother Knows Best. Peikoff holds a B.A. in Journalism from New York University and an M.S. in Bioethics from Columbia University. She lives in New Jersey with her husband and two young sons. Follow her on Twitter @KiraPeikoff.
A historical perspective offers insights about how far we have come since the 1918 Spanish flu, and how far we have yet to go.
With a deadly pandemic sweeping the planet, many are questioning the comfort and security we have taken for granted in the modern world.
A century ago, when an influenza pandemic struck, we barely knew what viruses were.
More than a century after the germ theory, we are still at the mercy of a microbe we can neither treat, nor control, nor immunize against. Even more discouraging is that technology has in some ways exacerbated the problem: cars and air travel allow a new disease to quickly encompass the globe.
Some say we have grown complacent, that we falsely assume the triumphs of the past ensure a happy and prosperous future, that we are oblivious to the possibility of unpredictable "black swan" events that could cause our destruction. Some have begun to lose confidence in progress itself, and despair of the future.
But the new coronavirus should not defeat our spirit—if anything, it should spur us to redouble our efforts, both in the science and technology of medicine, and more broadly in the advance of industry. Because the best way to protect ourselves against future disasters is more progress, faster.
Science and technology have overall made us much better able to deal with disease. In the developed world, we have already tamed most categories of infectious disease. Most bacterial infections, such as tuberculosis or bacterial pneumonia, are cured with antibiotics. Waterborne diseases such as cholera are eliminated through sanitation; insect-borne ones such as malaria through pest control. Those that are not contagious until symptoms appear, such as SARS, can be handled through case isolation and contact tracing. For the rest, such as smallpox, polio, and measles, we develop vaccines, given enough time. COVID-19 could start a pandemic only because it fits a narrow category: a new, viral disease that is highly contagious via pre-symptomatic droplet/aerosol transmission, and that has a high mortality rate compared to seasonal influenza.
A century ago, when an influenza pandemic struck, we barely knew what viruses were; no one had ever seen one. Today we know what COVID-19 is down to its exact genome; in fact, we have sequenced thousands of COVID-19 genomes, and can track its history and its spread through their mutations. We can create vaccines faster today, too: where we once developed them in live animals, we now use cell cultures; where we once had to weaken or inactivate the virus itself, we can now produce vaccines based on the virus's proteins. And even though we don't yet have a treatment, the last century-plus of pharmaceutical research has given us a vast catalog of candidate drugs, already proven safe. Even now, over 50 candidate vaccines and almost 100 candidate treatments are in the research pipeline.
It's not just our knowledge that has advanced, but our methods. When smallpox raged in the 1700s, even the idea of calculating a case-fatality rate was an innovation. When the polio vaccine was trialled in the 1950s, the use of placebo-controlled trials was still controversial. The crucial measure of contagiousness, "R0", was not developed in epidemiology until the 1980s. And today, all of these methods are made orders of magnitude faster and more powerful by statistical and data visualization software.
If you're seeking to avoid COVID-19, the hand sanitizer gel you carry in a pocket or purse did not exist until the 1960s. If you start to show symptoms, the pulse oximeter that tests your blood oxygenation was not developed until the 1970s. If your case worsens, the mechanical ventilator that keeps you alive was invented in the 1950s—in fact, no form of artificial respiration was widely available until the "iron lung" used to treat polio patients in the 1930s. Even the modern emergency medical system did not exist until recently: if during the 1918 flu pandemic you became seriously ill, there was no 911 hotline to call, and any ambulance that showed up would likely have been a modified van or hearse, with no equipment or trained staff.
As many of us "shelter in place", we are far more able to communicate and collaborate, to maintain some semblance of normal life, than we ever would have been. To compare again to 1918: long-distance telephone service barely existed at that time, and only about a third of homes in the US even had electricity; now we can videoconference over Zoom and Skype. And the enormous selection and availability provided by online retail and food delivery have kept us stocked and fed, even when we don't want to venture out to the store.
Let the virus push us to redouble our efforts to make scientific, technological, and industrial progress on all fronts.
"Black swan" calamities can strike without warning at any time. Indeed, humanity has always been subject to them—drought and frost, fire and flood, war and plague. But we are better equipped now to deal with them than ever before. And the more progress we make, the better prepared we'll be for the next one. The accumulation of knowledge, technology, industrial infrastructure, and surplus wealth is the best buffer against any shock—whether a viral pandemic, a nuclear war, or an asteroid impact. In fact, the more worried we are about future crises, the more energetically we should accelerate science, technology and industry.
In this sense, we have grown complacent. We take the modern world for granted, so much so that some question whether further progress is even still needed. The new virus proves how much we do need it, and how far we still have to go. Imagine how different things would be if we had broad-spectrum antiviral drugs, or a way to enhance the immune system to react faster to infection, or a way to detect infection even before symptoms appear. These technologies may seem to belong to a Star Trek future—but so, at one time, did cell phones.
The virus reminds us that nature is indifferent to us, leaving us to fend entirely for ourselves. As we go to war against it, let us not take the need for such a war as reason for despair. Instead, let it push us to redouble our efforts to make scientific, technological, and industrial progress on all fronts. No matter the odds, applied intelligence is our best weapon against disaster.