The stock market crashed on the same week as Joe’s fifteenth birthday. Living in a Jewish immigrant community in New York tenements, he watched as layoffs, breadlines, shantytowns, riots, suicides, and all-around human misery engulfed his city. Joe had dreamed of growing up and helping alleviate the suffering around him ever since he’d witnessed coffin-filled wagons passing his parents’ apartment during the Spanish Flu pandemic of his early childhood. Now, the Great Depression reinforced for him that the world was hurting, and it deepened his desire to help it. His parents had taught him the Jewish principle of tikkun olam: repairing the world. He intended to live his life by it, and planned to become an attorney who would fight on behalf of the marginalized.

As it turned out, Joe did have a chance to rise out of the poverty in which he grew up and pursue his dream, because Joe happened to be quite smart. He skipped several grades, and he was rarely spotted without a book in his hands. An elite college preparatory school in his community of Jewish immigrants accepted him. He was the first member of his family to go to college.

But as Joe continued his education, it became evident that his academic performance among other smart people was merely average. He had an overall B- grade at the end of high school. He enrolled at the City College because it was well-respected, free, and his family had no money to send him elsewhere. Once there, he promptly got Cs in chemistry, English, and math. Very reserved, he made no significant impressions on his classmates, earned no distinctions, and participated in no student organizations.

Joe’s mom tried to talk him out of his plan to become a lawyer. His shyness and his eagerness to avoid conflict didn’t suit the profession, she said. And not only that, he’d never won an argument with her. She suggested he become a teacher and help the world through education.

She succeeded in persuading him that the legal field was a poor personal fit for him. But Joe didn’t think teaching quite fit the bill for maximizing his positive impact on the world.

He asked his mother about the medical field. She thought he’d be unable to tolerate the long hours. But despite no prior interest in science, he switched to a premed track in college and applied to several medical schools. A single mediocre school accepted him. Still determined to make a difference somehow, he enrolled.

Throughout medical school, Joe lived with his parents and worked a part-time job to pay for tuition and equipment. He became interested in research, particularly on microbes and on preventing disease. Doing large-scale research work that could help humankind in general appealed more to him than helping patients on a one-to-one basis. When a professor cautioned that a career in research would never make him rich, Joe told him, “There is more in life than money.”

During med school, he was drawn to a graduate student in sociology named Donna because she cared about social justice and wanted to be a humanitarian like him. Despite his average looks and middling prospects, she was attracted to him too, but unfortunately for them both, Donna’s wealthy father didn’t approve of the relationship. He saw Joe as beneath Donna’s station.

Nevertheless, they persuaded him to accept their marriage on the condition that they wait until after Joe graduated to announce the wedding, so everyone invited could see the “MD” after his name. United by their profound caring for others, Donna and Joe married as soon as he graduated.

After Joe finished his residency, he found that many research institutions wouldn’t hire him because he was Jewish. But he eventually found a position researching influenza in the large clinical vaccine trials during World War II. Striking back at that virulent phantom from his childhood, he served on a small team that created the first influenza vaccine, which was used to vaccinate the entire U.S. Army. This work led—for the first time in Joe’s life—to a stable, long-term job after the war. He became a professor of epidemiology.

The job swallowed him, and with an hour-and-a-half commute, he spent most of his time away from his family. But Joe was driven, and even though his lab was small and poorly funded, his work during the war had positioned him to continue his research during peacetime. Still aiming to do the most good for the most people possible, he made it his mission to develop a universal flu vaccine that would protect against all influenza strains.

One day, the research director of the National Foundation for Infantile Paralysis (NFIP) approached him about a new project. The NFIP was funding basic research into the virus that caused poliomyelitis and wanted to learn how many types of the virus existed.

Our hero Joe—or as history knows him, Jonas Salk—wasn’t particularly interested in polio. But he saw the polio typing project as an opportunity to get funding for his lab so he could pursue his primary objective of a universal flu vaccine. So he agreed.

Although people who worked with Salk enjoyed his bedside manner and sense of humor, he was not well-liked by the scientific community. He relished science communication during a time when science and academia were insulated from the rest of society. He spoke often to the public and the press. Even for a time after he became a public figure, Salk answered every single letter sent to his lab, including some hard ones from people with polio, because he cared about people’s health.

But senior scientists saw this behavior as attention-seeking. Salk also tended to publish somewhat speculative papers without enough evidence to support his conclusions, and he occasionally commented on results to the press that hadn’t yet been peer-reviewed. Not to mention, safety conditions in his lab weren’t great, and several times glass containers with live polio inside shattered due to mishandling.

And now a nonprofit charity organization held the purse strings for Salk’s scientific research—an unheard-of concept at the time. His lab was also collaborating with other labs in the program, which was unusual. Some top scientists didn’t consider Salk a serious researcher.

At an NFIP round table Salk attended, virologist Isabel Morgan mentioned that during the process of determining what strain of polio some samples belonged to, she’d performed rudimentary polio vaccination of rhesus monkeys in her lab using dead poliovirus. Salk’s mind immediately jumped to the question: “Why aren’t we doing this for humans?”

Most virologists thought a vaccine was still years away for various technical reasons, with the linchpin being that only a vaccine containing weakened live poliovirus would be acceptable to them. They thought a killed vaccine wouldn’t confer long-lasting immunity. But the problem as Salk saw it was that a live, weakened vaccine would take years longer to develop. The virus would need to be passed through hundreds of monkeys, one at a time, to lessen its virulence. If he could find evidence that the killed virus would cause lasting immunity, however, he could save many thousands of lives now.

Focusing on two diseases at once, Salk’s workload grew too great, and the polio problem suddenly seemed much more tractable than the influenza problem. So as close to his heart as fighting influenza was, Salk dropped all of that research to focus on polio.

And indeed, polio was a killer. Seven thousand died from it in a 1916 U.S. epidemic. Severe cases presented with fever and uncompromising pain, followed, in some cases, by limb paralysis and/or difficulty breathing, which was sometimes permanent. Each summer in the 1950s, dread descended over parents across the world as they hoped and prayed their children would be spared. With a multitude of asymptomatic carriers, polio was difficult to control using normal public health measures.

President Roosevelt, a polio victim himself, had popularized the fight against it and helped form the NFIP, which was now funding Salk’s research. Over two million NFIP volunteers labored throughout the United States to raise money at movie theaters, churches, and thousands of local chapters for what became known as the March of Dimes.

While the other teams on the research project were still performing basic research on the virus, Salk secretly set his team to work on a killed-virus vaccine. Three months later, they’d developed one.

When Salk presented the vaccine to the NFIP committee assigned to oversee the research, they refused to let him do human trials because they thought there was no way to make sure all the viruses in the vaccine had actually been killed. Despite the ample proof Salk provided that the viruses had indeed been killed, and that immunity after three doses was just as high as immunity after natural infection, they saw his vaccine as a fool’s errand. They were perhaps overeager to avoid the mishap of rushing a vaccine through research trials only for it to accidentally infect the very people it was supposed to protect—a tragic blunder that had happened during an earlier attempt at a polio vaccine.

The NFIP’s research director, however, told Salk to go for it—in secret. He approved a series of small human trials for Salk’s vaccine, and it proved to be safe and effective. “It was the thrill of my life,” Salk said about the moment he first saw the results. When he came home from work that night, he ran through his front door and exclaimed to his family, “I’ve got it!”

When he presented the results to the NFIP committee, they ripped him apart. They said it needed more animal testing, more research needed to be done to find the proper strains, and they needed to determine whether an oral or injectable vaccine would be best, among numerous other concerns. A minority of the committee fought back, arguing Salk’s vaccine should proceed immediately to a large-scale clinical trial, though Salk thought this was a bit premature. Lives hung in the balance as they debated.

The fact that a field trial was being considered was leaked to the press, and the news ran with it. After embellished promises from the media, the world expected a vaccine trial, and the NFIP’s leadership wanted one. Salk, appearing humble and competent in interviews, became tied to the vaccine trials in the public’s eye, despite the fact that the NFIP, not Salk, was in total control of them.

Much to his chagrin, he became a minor celebrity. He didn’t like the media’s term “Salk vaccine” because he wanted to share the credit with everyone else whose ideas and efforts had helped develop it. In one interview, perhaps to answer both the media who sensationalized him and the virologists who wanted to spend endless years on further research, Salk said, “It is not for the glorification of the individual, but for the service of humanity that [research] should be oriented. The goal should be to solve a problem and not merely to work on a problem.”

The only organizations with the capacity to produce enough vaccines for a large trial were pharmaceutical companies, but the process of creating the vaccine was extremely complex, and Salk didn’t trust them to do it right. He wrote detailed instructions and spent a vast amount of time on the phone explaining it all to pharma techs. No one on his team could describe the procedure to them in full—Salk was literally the only person in the world who knew how to make the vaccine accurately.

He stipulated that he be allowed to conduct his own safety tests on each batch of vaccine in addition to the tests pharma companies performed. It was a good thing, too. The companies introduced cost-saving measures that ignored some of the details in his instructions. Safety checks caught live viruses in some vaccines being prepared for the trial.

Unfortunately, this story also leaked to the press, which sensationalized it. The trials lost over a third of their volunteers due to parents’ justifiable fear the vaccine would harm their children. Salk started getting hate mail. One critical article began with “Only God above will know how many thousands of little white coffins will be used to bury the victims of Salk’s heinous, fraudulent vaccine.”

But before long, one of the largest randomized controlled trials in history began all the same, with two million American children as its subjects. Antibody levels would be measured before and after vaccination, and the rate of polio incidence would be recorded in an experimental group and a control group.

IBM punch-card computers analyzed the data. Close friends and even celebrities contacted Salk to beg for vaccines for their family before it was approved. He was thoroughly burnt out by this time, and even developed chest pains. He started seeing a psychiatrist to treat anxiety caused by overwork.

When the trial’s results were announced on April 12, 1955, Salk was still its poster boy, even though he hadn’t designed or implemented the trial. The press coverage was massive. Reporters swarmed a group of researchers carrying reports of the results and leaked the news fifty minutes early. The world breathed a collective sigh of relief as it learned Salk’s vaccine was safe, and was 80–90% effective at preventing poliomyelitis.

From Charlotte DeCroes Jacobs’s biography Jonas Salk: A Life, by which much of this post is informed:

Church bells tolled, horns honked, and sirens rang out as the nation rejoiced. Some cheered; some cried. In department stores, loudspeakers blared out the good news. Storekeepers painted “Thank You Dr. Salk” on their windows. Public address systems in schools, courtrooms, and factories called for a moment of silence.

Parents across the world celebrated. In the coming months, streets, hospitals, and monuments were named after Salk. People mailed him money and even sent him new cars in thanks, but he returned it all to the senders, encouraging them to buy vaccines for their local communities. Marlon Brando sent Salk a thank-you message, and the Academy Awards invited him to attend. Numerous universities offered him honorary degrees. President Eisenhower gave him a citation. His incoming mail volume jumped to over 10,000 letters per month, and he could no longer respond to them all.

The Department of Health, Education, and Welfare (the precursor to today’s Department of Health and Human Services) licensed Salk’s vaccine the very same day the trial’s results were announced. The story is often told that Salk chose not to patent the vaccine, but this isn’t quite correct, because the vaccine was unpatentable. It was based on too many distinct discoveries by too many separate scientists. It is true, though, that Salk chose not to pursue profit from his vaccine so that it could be freely disseminated around the world. Most developed countries produced their own version of Salk’s vaccine within a year.

In the U.S., the vaccine rollout was very bumpy, and much work remained to rid developing nations of polio. But year after year, humanity had less and less use for iron lungs. The fear that had seized parents each summer abated. Children who otherwise would have died or suffered partial paralysis instead grew up polio-free.

How many lives did the Salk vaccine save? Reliable global polio statistics weren’t kept at the time, but worldwide, polio likely caused hundreds of thousands of cases and tens of thousands of deaths each year. Albert Sabin, one of the naysayers on the NFIP committee, finally developed a weakened live vaccine about six years after Salk developed his. During those six years, the Salk vaccine likely prevented around 200,000 cases and 12,000 deaths in the United States alone. The global estimate would be much higher.

Jonas Salk was not a saint. Far from it. Early in his career, before modern ethical standards for research were established, he helped lead a study that intentionally infected two hospitals for the mentally ill with influenza in order to test a vaccine. Thousands of rhesus monkeys were killed during Salk’s experiments while developing the polio vaccine. A notorious workaholic, his family life was far from perfect. And the meandering, grandiose second half of his life offers many examples of what not to do if one finds oneself wildly successful and famous.

Perhaps these shortcomings and actions lower him from his perceived sainthood, closer to the level of an average person. But in any evaluation of the man’s life, the tremendous good he did for humanity should be taken into account, as well as the key perspectives and choices that led to his achievement.

Salk’s story fits neatly into the American mythos of hard work and determination raising a visionary out of poverty to accomplish great things and prosper as a result. And history books acknowledge his wisdom in noticing his peers were neglecting to see that mass vaccination with a killed virus would be possible six years earlier than with a weakened live virus.

But often overlooked are crucial decisions such as Salk’s choice to pursue medical school when he realized law wasn’t a good fit for him, or his choice to leave his beloved influenza research, on which he’d expended much time and energy, to pursue the more promising project of a polio vaccine. How different would the 1950s have been for the world if Salk had taken a different path with what were seemingly personal choices? Who would be the unlucky ones who’d have later perished from an unchallenged polio?

Salk’s story also demonstrates that an altruist doesn’t have to be the best of the best to have important insights or achieve something great for humanity. He was bright but not the brightest, he went to what was at the time a second-rate medical school, and he wasn’t as well-funded or well-connected as many of the other researchers working on the NFIP’s polio project. And yet he made a contribution more significant and impactful than most people ever have.

Also important to the development of the polio vaccine was Salk’s general altruistic outlook (despite the fact that some of his actions ended up being harmful). He saw it as his life’s mission to lessen suffering. When he could have worked as a doctor and lessened suffering one patient at a time—which is undeniably valuable, important work—Salk nevertheless thought bigger, recognizing that the scale of problems is a key factor that should matter when we decide whether to work on them. And in the end, when others with his career trajectory might have grown distracted by the prospects of money and prestige, he maintained that there is more in life than money, especially the principle he’d learned as a child, tikkun olam: repairing the world.