All achievers

Jonas Salk, M.D.

Developer of the Polio Vaccine

Risks, I like to say, always pay off. You learn what to do or what not to do.

In America in the 1950s, summertime was a time of fear and anxiety for many parents; this was the season when children by the thousands became infected with the crippling disease poliomyelitis, or polio. This burden of fear was lifted forever when it was announced that Dr. Jonas Salk had developed a vaccine against the disease. Salk became world-famous overnight, but his discovery was the result of many years of painstaking research.

Jonas Salk was born in New York City. His parents were Russian-Jewish immigrants who, although they themselves lacked formal education, were determined to see their children succeed, and encouraged them to study hard. Jonas Salk was the first member of his family to go to college. He entered the City College of New York intending to study law, but soon became intrigued by medical science.

American scientist and physician Jonas Salk (1914 - 1995), developer of the polio vaccine, holding up a bottle in the laboratory, mid twentieth century. (Archive Photos/Getty Images)
Dr. Jonas Salk (1914-1995), developer of the polio vaccine, holding a bottle in the laboratory, mid-20th century.

While attending medical school at New York University, Salk was invited to spend a year researching influenza. The virus that causes flu had only recently been discovered, and the young Salk was eager to learn if the virus could be deprived of its ability to infect, while still giving immunity to the illness. Salk succeeded in this attempt, which became the basis of his later work on polio.

After completing medical school and his internship, Salk returned to the study of influenza, the flu virus. World War II had begun, and public health experts feared a replay of the flu epidemic that had killed millions in the wake of the First World War. The development of vaccines controlled the spread of flu after the war, and the epidemic of 1919 did not recur.

In 1947, Salk accepted an appointment to the University of Pittsburgh Medical School. While working there, with the National Foundation for Infantile Paralysis, Salk saw an opportunity to develop a vaccine against polio, and devoted himself to this work for the next eight years.

Dr. Jonas Salk, who developed the vaccine that is believed to have struck the death knell of polio, is shown (left) as he received a special citation from President Dwight David Eisenhower in the White House Rose Garden. The President praised the young doctor as a 'benefactor of mankind' and said that his work was in the 'highest tradition of selfless and dedicated research.' At right is Mrs. Oveta Culp Hobby, Secretary of Health, Education, and Welfare. Meanwhile, government officials and medical and pharmaceutical representatives were conferring on the procedure for distributing the vaccine. April 23, 1955. (Bettmann/Getty)
April 23, 1955: Dr. Jonas Salk, who developed the vaccine that is believed to have struck the death knell of polio, as he received a special citation from President Dwight David Eisenhower in the White House Rose Garden. The President praised the young doctor as a “benefactor of mankind” and said that his work was in the “highest tradition of selfless and dedicated research.” At right is Mrs. Oveta Culp Hobby, Secretary of Health, Education, and Welfare. Meanwhile, government officials and medical representatives were conferring on distributing the vaccine.

In 1955, Salk’s years of research paid off. Human trials of the polio vaccine effectively protected the subject from the polio virus. When news of the discovery was made public on April 12, 1955, Salk was hailed as a miracle worker. He further endeared himself to the public by refusing to patent the vaccine. He had no desire to profit personally from the discovery, but merely wished to see the vaccine disseminated as widely as possible.

1973: Jonas Salk, and his wife, French painter Françoise Gilot. In 1969, during an exhibition in Los Angeles, Françoise traveled to La Jolla and was introduced to Dr. Jonas Salk. Their mutual admiration of architecture prompted Dr. Salk to offer Françoise a tour of The Salk Institute. It was a brief courtship were soon married in 1970 in Paris. They remained married until Salk's death in 1995. (Photo by Albane Navizet/Kipa/Sygma via Getty Images)
1973: Jonas Salk, and his wife, French painter Françoise Gilot. “In 1969, during an exhibition in Los Angeles, Françoise traveled to La Jolla and was introduced to Dr. Jonas Salk. Their mutual admiration of architecture prompted Dr. Salk to offer Françoise a tour of The Salk Institute.” They married in 1970 in Paris and were together for twenty-five years until Salk’s death in 1995. (Photo Credit: Albane Navizet/Kipa/Sygma viaGetty Images)

Salk’s vaccine was composed of “killed” polio virus, which retained the ability to immunize without running the risk of infecting the patient. A few years later, a vaccine made from live polio virus was developed, which could be administered orally, while Salk’s vaccine required injection. Further, there was some evidence that the “killed” vaccine failed to completely immunize the patient. In the U.S., public health authorities elected to distribute the “live” oral vaccine instead of Salk’s. Tragically, the preparation of live virus infected some patients with the disease, rather than immunizing them. Since the introduction of the original vaccine, the few new cases of polio reported in the United States were probably caused by the “live” vaccine which was intended to prevent them. In countries where Salk’s vaccine has remained in use, the disease has been virtually eradicated.

In 1963, Salk founded the Jonas Salk Institute for Biological Studies, an innovative center for medical and scientific research. Jonas Salk continued to conduct research and publish books, some written in collaboration with one or more of his sons, who are also medical scientists.

Dr. Jonas Salk at the Salk Institute Febuary 25, 1975 in La Jolla, California. He was the first researcher to develop a safe and effective vaccine for polio. (Photo by Arnold Newman/Getty Images)
February 25, 1975: Dr. Jonas Salk at the Jonas Salk Institute for Biological Studies in La Jolla, California. He was the first researcher to develop a safe and effective vaccine for polio. (Photo by Arnold Newman/Getty Images)

Salk’s published books include Man Unfolding Salk’s plea to “look at human life from a biological viewpoint” (1972), The Survival of the Wisest (1973), World Population and Human Values: A New Reality (1981), and Anatomy of Reality (1983).

Dr. Salk’s last years were spent searching for a vaccine against AIDS. Jonas Salk died on June 23, 1995. He was 80 years old. The 100th anniversary of his birth in 2014 was the occasion for renewed appreciation and celebration of Dr. Salk’s contribution to humanity.

Inducted Badge
Inducted in 1976

“We were told in one lecture that it was possible to immunize against diphtheria and tetanus by the use of chemically-treated toxins, or toxoids. And the following lecture, we were told that for immunization against a virus disease, you have to experience the infection, and that you could not induce immunity with the so-called ‘killed’ or inactivated, chemically-treated virus preparation. Well, somehow, that struck me. What struck me was that both statements couldn’t be true. And I asked why this was so, and the answer that was given was in a sense, ‘Because.’ There was no satisfactory answer.”

Jonas Salk was still a student when he began to look for a better answer to his classroom question, and the answer he found led to one of the most dramatic breakthroughs in the history of medicine.

In America in the 1950s, summertime was a time of fear and anxiety for many parents; this was the season when children by the thousands became infected with the crippling disease poliomyelitis, or polio. That burden of fear was lifted forever when it was announced that Dr. Jonas Salk had developed a vaccine against the disease. Salk became world-famous overnight, but his discovery was the result of many years of painstaking research.

Salk went on to found the Jonas Salk Institute for Biological Studies in La Jolla, California, where he continued his research into the causes, prevention and cure of diseases such as cancer and AIDS. Dr. Salk never patented his polio vaccine, but distributed the formula freely, so the whole world could benefit from his discovery.

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When did you first have a vision of what you might accomplish in the field you chose?

Jonas Salk: You never have an idea of what you might accomplish. All that you do is you pursue a question. And see where it leads. The first moment that a question occurred to me that did influence my future career, occurred in my second year at medical school. Although you must understand, all of the events that occurred before laid the foundation in a way. And if those events had not occurred, then that moment would have passed by quite differently. But as I tell the story…

We were told in one lecture that it was possible to immunize against diphtheria and tetanus by the use of chemically-treated toxins, or toxoids. And the following lecture, we were told that for immunization against a virus disease, you have to experience the infection, and that you could not induce immunity with the so-called “killed” or inactivated, chemically-treated virus preparation. Well, somehow, that struck me. The way it struck me was that both statements couldn’t be true. I asked why this was so, and the answer that was given was, in a sense, “Because.” There was no satisfactory answer.

Perhaps it had been tried and had not succeeded. There had not been any success. And I think that in fact was true. But it was some two years later, I think it was, that…

I had an opportunity to spend time in elective periods in my last year in medical school, in a laboratory that was involved in studies on influenza. The influenza virus had just been discovered about a few years before that. And I saw the opportunity at that time to test the question as to whether we could destroy the virus infectivity and still immunize. And so, by carefully designed experiments, we found that it was possible to do so.

That was how that particular line of investigation, you might say — and it influenced my career — occurred.  It was, in a sense, a paradox.  It didn’t make sense, and that question persisted in my mind.  I had forgotten about it in the interim.  I was pursuing another path, I was interested in chemistry, I was interested in the rheumatic diseases, and since I was not able to pursue that in that particular lecture period, and by chance I found myself in this laboratory, I pursued that question, from then on. I interrupted those studies because I graduated from medical school and interned. The war broke out, influenza was important, and I continued on in research in that field, developed a flu vaccine, and that led to all sorts of other things.

Dr. Jonas Salk in the laboratory. (March of Dimes Birth Defects Foundation)
Dr. Jonas Salk in the laboratory. (March of Dimes Birth Defects Foundation)

How did your work with the polio vaccine come about?

Jonas Salk: After my internship, in ’42, I went to Ann Arbor, Michigan. I was there until ’47, then went on to Pittsburgh, to be somewhat independent of my mentor. The opportunity in Pittsburgh was something that others did not see, and I was advised against doing something as foolish as that because there was so little there. However, I did see that there was an opportunity to do two things. One was to continue the work I was doing on influenza, and two, to begin to work on polio. That was a very modest beginning.

Within a few months after I arrived in Pittsburgh, I was visited by the director of research of the National Foundation for Infantile Paralysis, asking if I would be willing to participate in a program on typing polio viruses. I’d had no experience in working with polio, but this provided me with an opportunity, just as the work on influenza did. So I seized upon that opportunity. It gave me a chance to get funds, to get laboratory facilities, to get equipment, to hire staff, and to build up something that was not there. It also would provide me with an opportunity to learn about how you work with the polio virus.

That experience was looked upon by most people as routine drudgery. It wasn’t that way to me, because instantly I saw that there were more efficient ways of typing viruses than were proposed by those who set forth the protocol that I was supposed to follow. It didn’t take long for them to realize that I saw the world differently, and that I could make things work more efficiently and effectively. In the course of that work, it became obvious to me that we had the ways and means for moving ahead toward vaccine development. We knew there were three types of the virus. John Enders, Thomas Weller, and Frederick Robbins at Harvard had just grown the virus in tissue culture. I didn’t delay. I didn’t waste any time, just picked up these methods and techniques, and began to advance them even further ahead than those who initiated the work. By putting the bits and pieces together, I moved very quickly into studies in animals, and then on humans.

Dr. Salk vaccinates a child against polio. (March of Dimes Birth Defects Foundation)
Dr. Jonas Salk vaccinates a child against polio. (March of Dimes Birth Defects Foundation)

What attracted you to the notion of using a killed vaccine? That goes back to your influenza work, doesn’t it?

Jonas Salk: The reason for pursuing the idea of a killed virus vaccine is very simple. Before the work on influenza, the effective vaccines were those made with what we call attenuated, or so-called weakened viruses. They have the capacity to infect, but they are less likely to cause disease. Now sometimes smallpox or vaccinia virus — which is the same virus that is used to make immunization against smallpox — would cause serious reactions, and sometimes fatal reactions. There was a rabies vaccine that was made from weakened viruses. There was also a yellow fever vaccine that had been developed that was a weakened virus.

The principle that I tried to establish was really that it was not necessary to run the risk of infection, which would have been the case if one were to try to develop an attenuated or weakened polio virus vaccine. And so it seemed to me the safer and more certain way to proceed. That if we could inactivate the virus that we could move on to a vaccine very quickly. Whereas, if you were dealing with weakened virus, you would have to demonstrate its safety eventually. So that was the reasoning and there was a principle that was involved. You might say a scientific principle, a fundamental principle: choosing and preferring that which — the safety which you could control, and the quantities which you could use. So that this is, in a way, a more scientific approach. Trying to work like nature, instead of imitating nature.

Therefore, I wanted simply to select a variant that was weakened, you might say. At that time I was behaving like a medical scientist. Exploring the limits within which one could effectively immunize with a non-replicating, non-multiplying virus. So, it was not a matter of why I chose that. I was investigating to see whether it could be done — and it could be done.

And, then we determined the parameters within which, in terms of dose and quantity and duration and persistence, and what kind of immunity, if an immune response was required. And that way, I began to develop an understanding of the principles of vaccinology as applied to polio miletus as well as influenza. So, that was the attitude that prevailed at that time. It was not simply empirical. It was a theoretical experimental approach.

Dr. Jonas Salk's discovery of the polio vaccine made headlines all around the world. (March of Dimes Birth Defects Foundation)
Dr. Jonas Salk’s discovery of the polio vaccine made headlines all around the world. (March of Dimes Foundation)

You got quite a bit of flack for that because no one had done it before, and you were going out on a limb.

Jonas Salk: I wasn’t going out on a limb. The flack to which you refer is what taught me, very early on, not only about the human side of nature, but about the human side of science.

Keys to success — Perseverance

There are three stages of truth. First, is that it can’t be true, and that’s what they said. You couldn’t immunize against polio with a killed-virus vaccine. Second phase, they say, “Well, if it’s true, it’s not very important.” And the third stage is, “Well, we’ve known it all along.” What you are describing is the process that you have to go through when you come up with an idea that has not yet been tried or tested. While it is true that this involves personalities, it also involves different ways of seeing. It was not a matter of a popularity contest, it was not a matter of anything other than that my curiosity drove me to find out whether it could work or not.