30 Years After 1st Vaccine, Dr. Jonas Salk Still Strives to Eradicate Polio
Thirty years ago, the onset of summer each year brought not only warm weather but the potential of a polio outbreak. Millions of parents feared that their children might contract the paralyzing disease if they were allowed to congregate at swimming pools or movie theaters.
Then, on April 12, 1955, the long-awaited announcement was made: Dr. Jonas Salk’s polio vaccine had been proven safe and effective in massive field trials among almost 2 million schoolchildren.
The entire nation reacted with joy and relief that a scourge through the millenniums would finally be brought under control. It was a measure of the importance attached to the announcement in Ann Arbor, Mich., that then-President Dwight D. Eisenhower decided immediately to spread the vaccine information worldwide, and to include Soviet Bloc countries.
Today, a generation of Americans has grown up without knowing the crippling effects of polio epidemics, without needing to undergo agonizing rehabilitation and training in using crutches.
But while the 30th anniversary finds polio an epidemic of the past in the United States, it still ravages half a million people around the world annually, including 200,000 every year in India alone. And those statistics dampen the satisfaction that Salk takes as a scientist in having discovered how to trick nature with his vaccine.
For that reason, Salk’s active interest in polio continues today, in particular on ways to make the vaccine easier to administer, especially in developing countries. His ruminations on evolution and the nature of human thinking, which increasingly occupy a large part of his time, have themselves developed in part from the slowness of obtaining worldwide use of immunization.
“I think only of the places where polio still occurs,” Salk said during an interview last week when asked his thoughts on the anniversary. “We have the means to eradicate polio, which we will do some day, and that has occupied my attention for some time.
“In trying to understand how to do so, I have been led to my more general observations about human nature.”
Salk met with world health officials on ways to accelerate polio eradication while on an East Coast trip last week.
For Salk, the problem can be posed this way: “Where there is a will, there is a way. Why was a vaccine developed? Where the will was, a way was found. But now it is crucial to ask: ‘Where there is a way, is there the will?’
“There is a seeming paradox that the means to control a crippling disease exists, yet 30 years later, we are still tolerating a certain number of cases . . . how to help people do what is in their best interest?
“These are fascinating questions and that is why my life is not dull.”
Salk now lives in La Jolla, where his office overlooks the Pacific Ocean in a corner of the biological institute that bears his name. At age 70, he remains active in a variety of endeavors, all involving fundamental questions of scientific disciplines within a philosophical framework.
But Salk can trace what he calls the process of his work--”akin to moving into the future without a map”--to his early days researching the viral nature of influenza and polio.
The key to Salk’s vaccine was the idea of destroying, with chemicals, the ability of the polio virus to cause disease when injected into the human body, but retaining the virus’s ability to stimulate production of antibodies.
Salk’s killed, or non-infectious, vaccine produces antibodies that later can stop an invasion of polio virus from natural causes. Its widespread use after the 1954 field trials resulted in a 97% decline in the number of new polio cases by 1962, when a live virus vaccine was licensed for use by government health officials. (That vaccine is the so-called oral Sabin vaccine.)
“I was confused in immunology courses (while studying to be a physician) when told that we can use chemically treated toxins for vaccines such as tetanus but not for viral agents, such as influenza or polio,” Salk said. Salk discovered to the contrary that chemical treatment of viruses was theoretically possible as a result of his wartime influenza research.
“The effort was to understand the mechanism in disassociating infection from protection,” he said.
Even today, Salk still prefers the non-infectious approach, saying that the “tricking of nature” approach is not only more elegant but also safer than imitating nature by giving the human body a live virus and running a risk, however minuscule, of causing the actual disease.
Salk regrets the failure as yet of many developing countries to apply immunization procedures that could eliminate polio completely, just as smallpox has been eradicated worldwide.
“There can be a last case of polio,” he said, but it requires an appropriate strategy and eventually the use of the killed-virus vaccine.
Current procedures for inoculations using the Salk vaccine call for three or four vaccinations. (In developing countries, the vaccine is often combined with diphtheria and tetanus immunizations.) But such health concerns are not a high priority in many countries where daily survival can be all-consuming, and people often drop out of inoculation programs without completing the entire series.
Therefore, much of his ongoing polio work has centered on trying to reduce dosage requirements to the realities of the population, and encouraging better education about health.
“We know theoretically that we can immunize for life with a single dose,” Salk said, a goal that he hoped to achieve as early as 1953, but which has taken much longer. Now, researchers can measure the effect of a single potent dose in developing countries because of the percentage of persons who drop out of the multi-dose inoculation programs.
Salk noted that even in the United States, there was initial resistance, or lack of attention, to immunization in certain lower socioeconomic groups and in some rural areas. And he pointed out that today, while Americans look upon polio immunization as natural, they embrace with less enthusiasm ways to eliminate or reduce the health risks that result in lung cancer, cirrhosis of the liver, and other social-related diseases.
“The health risks from cigarettes, alcohol, drugs, teen-age pregnancies; we know them, we are enlightened on the problems, yet the conditions continue to prevail, from either ignorance or the lack of ability to exercise the will.
“So, at bottom, with both a microbial enemy and a human enemy, there is an uncharted human element to try and understand. My research on polio has led to questions of human nature; that the limiting factor (in applying science and technology) is now to improve upon human nature.”
Salk said that the results he achieved from his influenza and polio research derived in part from the fact that he was not a specialist.
“I was not in any of the special disciplines that I drew upon,” he said. “I approached the problem as someone trying to fit the parts to make a whole, as someone integrating a great deal of knowledge.”
The integration of knowledge from various fields on an even larger scale was Salk’s goal in establishing the institute in La Jolla in 1962, but it remains unfulfilled today.
“The institute has not gone in the direction of integrating scientific knowledge with philosophical and humanistic questions,” Salk said. “I had intended the institute to study not only the cause, prevention and cure of disease but also to understand the conditions for fulfilling the human potential.
“In essence, I see science as one with philosophy.”
Salk said that the current academic system for training scientists does not reward the people he calls integrators. “We must do something to place a value on those able to integrate large realms, to organize complexity, as does nature,” he said.
“The human future depends on it.”
