How the Salk vaccine works to fight polio (from 1955)
By Herman N Bundesen, MD – The Plain Speaker (Hazleton, Pennsylvania) May 13, 1955
The Salk polio vaccine works — we know that now. But how does it work?
Three types of virus
The vaccine developed by Dr. Jonas E. Salk consists of all three types of polio virus treated with a formaldehyde solution to make them harmless.
When injected into a person, the vaccine induces the body to produce antibodies as a defense against the invasion. We can’t explain just what these antibodies are. We only know that they are small particles of protein manufactured by your body as the result of infection.
Protect body cells
Nor do we know precisely how these antibodies protect. In some manner, however, they appear to keep the virus from harming the body cells. Building up the antibody levels to attack the virus in the blood prevents the virus from getting to the nervous system and causing paralysis.
A few years ago, Dr. William Hammon, an epidemiologist at the University of Pittsburgh, found that small amounts of polio-fighting antibodies contained in gamma globulin from human) blood could confer temporary protection against the disease.
By injecting gamma globulin obtained from blood known to contain these antibodies, Dr. Hammon could confer temporary Immunity to polio. But these “loaned” antibodies lost their power In from six to eight weeks
The poliovirus itself, it was known, was capable of stimulating the human body into producing these antibodies to fight it. But the polio virus, of course, was also capable of producing paralysis or death.
Chemically treated
Dr. Salk solved this problem by treating the virus with chemicals that destroy its ability to cause disease. Yet the virus still stimulates production of antibodies to provide protection.
Polio vaccine is a great medical advance (1955)
Reports from the leaders in the polio vaccine field that the treatment is safe, efficient and potent marks another great advance in medical science.
Dr Thomas Francis Jr, who handled the statistics on the tests of last year, found the vaccine 80 to 90 percent effective on the basis of the tests. Dr JE Salk, for whom it is named, thinks it can be 100 percent effective when properly administered and handled it in shipment.
The report is filled with good news for the nation. One of the most encouraging statements is the fact it is extremely effective with bulbar polio, the most dangerous type. And the reactions among thousands of children have been minor. Only a fraction of one percent had any reaction. Major reactions were rare, and could not be traced directly to the vaccine, in most cases.
While the vaccine is thought to be effective only for about five months, booster shots may be taken to extend the effectiveness. But the five months will bridge the spring and early fall periods when polio seems to strike hardest.
While the remarkable tests have opened a great new field in medicine, there still is much to be learned, in the opinion of Dr Salk. He wants to know more about the proper spacing of shots. The fact that many children were given dummy shots in order to get a pattern of infection in some areas, while others had the real vaccine, apparently proved a valuable part of the experiment.
On the question of safety, Dr Francis said 931 children who were vaccinated and 939 given dummy shots had minor reactions, each the same percentage, .04.
Of the so called “major” reactions, none could clearly be attributed to inoculation. There were nine in children receiving the vaccine, and 13 such reactions those getting dummy shots. These finding failed to implicate the vaccine as a significant cause of untoward reactions. There was no evidence to blame the vaccine as a source of infection, the report declared.
Among children who developed paralysis, there was no evidence that the paralysis localized or involved the left arm where all injections were given.
Dr Francis said in the dummy-vaccine shot areas, the Salk vaccine was 68 percent effective against Type 1, 100 percent against Type 2, and 92 percent against Type 3.
“This clearly agrees with previous demonstrations that most lots of vaccine varied considerably as measured by the occurrence of polio,” Dr Francis said. He said it is not possible to give a single figure expressing the numerical or percentage effectiveness of the vaccine in a complete sense.
Dr Francis said there was no significant difference in the rates of non-paralytic polio in test and control groups.
Bulbar polio and spinal paralytic polio
Against bulbar polio, the vaccine was estimated to have been from 81 to 94 percent effective in preventing paralysis in the dummy shot control areas. The effect was less striking in spinal paralytic polio. About 60 percent down to a lower limit of 39 percent. From limited numbers of children tested in Canada and Finland, the vaccine also was credited with showing a significant effect.
Dr Salk declared the first two shots stimulate the production of antibodies in the bloodstream, and the child develops a state of readiness to make antibodies. His antibody-producing system becomes like a cocked revolver. The booster shot given at least seven months later serves as a trigger to produce remarkably high amounts of antibodies.
He said natural exposure to polio, if it occurs after the first two shots, also acts as a trigger to explode the antibody mechanism into action.
Dr Salk said the amount of antibodies induced by the seven to eight months spacing of the shots is higher than that brought about by paralytic infection itself.
Immunization safety
Some batches of vaccine used in the tests were overtreated with a preservative chemical, which in effect “fried” the dead virus, so much that it lost ability to stimulate antibodies, Dr Salk said.
Dr Salk declared last year’s study was a test of whether a “primary vaccination (three shots spaced in five weeks)” alone could prevent paralytic polio rather than a test of the effectiveness of what he called a full immunization by spacing the shots over a much longer period.
Thus, approximately two decades of effort by the National Infantile Paralysis Foundation has paid grand dividends. To the millions of people who have participated in the annual March of Dimes campaigns, goes a great deal of credit for financing the extensive research. And to the medical profession goes much more credit for keeping at what at times seemed an almost hopeless assignment.
When sufficient additional tests and refinements have been made, the medical profession will be ready to fully advise us on how the remarkable vaccine should be handled. Meanwhile, there appears to be every assurance that we have developed protection against one of the most dangerous of diseases.
Polio Continues to Strike (brochure from 1956)
In 1955 — the year in which the Salk polio vaccine was given to the world by March of Dimes research — some 30,000 Americans were stricken with infantile paralysis. It was the eighth consecutive year of the worst polio epidemics of all time.
Millions of children were protected through vaccine supplied by the March of Dimes. But, among the unprotected, polio still took its terrible toll.
In Massachusetts and Wisconsin, sweeping epidemics brought tragedy to thousands of homes. Throughout the nation, the disease served notice that polio is not licked yet. However grim the emergency, your National Foundation met the challenge with March of Dimes funds, equipment and personnel, contributing 18 years of experience to the battle against polio.
At the year’s end, there were 68,000 polio patients who would face 1956 looking to the March of Dimes for assistance. For them, the vaccine comes too late. But it is not too late to HELP. GIVE NOW — to the 1956 March of Dimes.
The Salk Vaccine
“The Salk vaccine is safe and effective.” That statement in April, 1955 climaxed months of study of the polio vaccine.
Your March of Dimes had poured millions of dollars into research leading to the vaccine’s development. It had paid for a fellowship for Dr. Salk. It financed the $7,500,000 vaccine field trials of 1954. It wisely invested your contributions in a multi-million dollar vaccine program to protect millions of school children during the 1955 polio season.
The world now recognizes the’ Salk vaccine as a landmark in medical history. But polio research has not ended.
► How long will immunity last?
► How can the vaccine be made more effective?
► How can vaccine be produced without the costly use of monkeys?
► Can a better vaccine be produced from live poliovirus?
► Can a preventive drug be developed to halt epidemics?
These questions must be answered. Professional workers must be trained for the continuing fight. New ways must be found to restore to a full life the crippled, the bed-ridden, the thousands imprisoned in iron lungs. The job is not finished.
Polio isn’t licked yet!
If you could walk through a polio ward today, you would understand why polio has not yet been conquered.
No vaccine can help the stricken. They’re crippled NOW. Their victories don’t make headlines. The smallest movement of a finger. A few blessed hours out of an iron lung. Learning to breathe by gulping air, like a frog. Taking a single step on crutches . . .
These are the small conquests that spark the existence of the stricken. These are the victories over polio which they earn through courageous effort— and YOUR help in the March of Dimes.
At 14 March of Dimes Respirator Centers, in countless hospitals across the nation, and even in patients’ homes, you are placing new goals within grasp of the severely stricken. Step by step, aided by the March of Dimes, those once without hope are hitting targets which, for them, spell victory over polio.
Their fight is a costly one. In 18 years, your March of Dimes has provided $233,000,000 in patient aid alone. The result: Human lives saved — men, women and children who will work and play again, free from the insult of crippling polio.
SURVIVAL: When paralysis hits the breathing muscles, the first battle is for life itself. A short time ago, death was almost certain. Today, March of Dimes respirators blanket the nation, on the alert. Rushed into emergency action, they score the first triumph over polio — SAVING LIVES!
FREEDOM FROM THE IRON LUNG: Survival, when it means imprisonment in an iron lung, is not enough. March of Dimes funds have developed new mechanical breathing aids— the chest respirator arid rocking bed. At Respirator Centers, MOST patients are quickly weaned from total dependence upon their steel jackets.
TO BREATHE WITHOUT HELP: Listen to yourself breathe. Suppose each breath depended upon power controlled by someone else? To shed all mechanical devices, to breathe again— without help— is the goal of thousands of patients served by your March of Dimes.
TO RISE UP: When polio’s first impact has passed, the struggle toward a useful life is just beginning. With new devices, one muscle may be taught to do the work of many. But one lone person, fighting for a new grip on life, must be helped by many, giving voluntarily to the March of Dimes.
TO LIVE AGAIN! This is the ultimate goal of the stricken— to be a person again … to support a family… to keep house … to go to school. These are victories over polio which must be won today, tomorrow and for years to come — through the March of Dimes.
