SALK VACCINE STILL GOOD

Editor’s Note: The following three Stories ran in The Pitt News on Wednesday, April 13, 1955…. Editor’s Note: The following three Stories ran in The Pitt News on Wednesday, April 13, 1955. The Pitt News is reprinting them today to commemorate yesterday’s 50th anniversary of the announcement of the vaccine’s success.

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Poliomyelitis, the dread disease which every year leaves thousands dead or crippled, has been conquered. In a report released yesterday from the polio center in Ann Harbor, Mich., Dr. Thomas Francis Jr. stated that the vaccine developed by Dr. Jonas Salk of the University of Pittsburgh is extremely effective and potent and “incredibly safe.” The long-awaited report came on the heels of the final tabulation of last spring’s mass test of 1,800,000 school children throughout the United States.

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Polio Vaccine Called Success

ANN HARBOR, April 12, 1955 — Dr. Thomas Francis today announced the results of the Salk polio vaccine field trials conducted last spring. His report marked the end of a half a century’s work and a brilliant victory over one of mankind’s most dread diseases.

Last spring’s trial run of the vaccine, in which 1,800,000 school children were inoculated, has been completely tabulated by Dr. Francis and his staff. The results show the vaccine to be almost 90 percent effective.

Dr. Francis stated that the vaccine, developed by a research team at the University of Pittsburgh headed by Dr. Jonas Salk, is safe, effective and potent. He specified that in patients with bulbar polio, which is the fatal and crippling type, the vaccine had produced “an extremely successful effect.”

A medical abstract of the 113-page evaluation report was prepared by Dr. Robert Korns, Dr. Francis’ deputy director of the vaccine evaluation program.

“In strong statistical language, the historic trial of the vaccine and its subsequent analysis was revealed,” according to the paper. “There can be no doubt now that children can be inoculated successfully against polio. There can be no doubt that humanity can pull itself up by its own bootstraps and protect its children from the insidious invasion of the ultra-microscopic disease.”

One death due to polio was reported from among the children who were vaccinated last spring. That child died following a tonsillectomy just two days after receiving the second polio shot. He did not receive the third and all-important “booster shot.” A polio epidemic was already forming in that locality.

Controls Get Placebo

The fatality occurred in one of the 33 states in which second grade pupils were vaccinated and first and third grade pupils were the “observed” controls for the test. In 11 states, some children received the vaccine while others were given shots of an inert substance called a placebo. Among these groups there were four deaths.

In the 33 observed control states there were 11 fatalities as a result of polio, which was contracted by children who did not receive the vaccine. But there were no deaths among those who did, with the exception of the one child who died following the second inoculation and the tonsillectomy. These circumstances demonstrated that the viruses were already incubating in the child before any vaccine was administered.

The way is now open for the government licensing and the manufacture by privately owned drug firms of enough vaccine to wipe out the disease in this country. They are ready to begin distribution at a moment’s notice.

Two Shots Enough

Dr. Salk reported that two shots of his vaccine are enough to prevent polio. This means that if the schedule he suggests is followed, 45 million children (all those in America under 15 years of age) can be given the vaccine before the end of this year if no adults request the shots.

Dr. Salk said that studies on children in Allegheny County during the past two years have convinced him that it is best to give two injections of vaccine two to four weeks apart, then follow up with a booster shot seven months later.

How long the booster will last he doesn’t know as yet. But he affirmed that it should be good for “years.” In one of his previous reports, he stated that the effectiveness should last for about two years.

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History of Polio Research Goes Back 50 Years

PITTSBURGH, April 13, 1955 — Yesterday’s announcement of victory over fatal and crippling polio fell upon the relieved ears of an expectant world. But to the researchers who have been working toward this goal, it came as no surprise but rather as the result of half a century’s work.

In 1909, doctors inoculated a monkey with material from a polio patient. The monkey contracted the disease. This marked the first time in history that the disease called poliomyelitis had been reproduced in an experimental animal.

The microbe which caused polio was so small that it could not be seen under the ordinary microscope, nor would it reproduce outside the living animal. This revealed that the cause of the disease was a virus. Thus, the first step in the conquest of the crippler had been taken.

Some 20 years ago, several thousand children were vaccinated against polio in a premature attempt to stem the disease. These vaccinations were unsuccessful and had to be discontinued. Later, when progress could be made more rapidly, it was necessary to bridge the gap created by the negative outcome of the first experience and to rebuild confidence that new efforts could be made safely and with reasonable expectation of success.

Then, in 1931, evidence was discovered which indicated that polio could be caused by more than one virus. Almost 20 years of research were expended before it was proven that three different types of virus existed, each capable of causing polio. A systematic study, completed in 1951, indicated that no more than the three known types existed.

Individual Immunization Needed

Further study showed all three types to be similar. The difference lay in that each would immunize only against viruses of the same type but not against the other two types. Thus, a person who had experienced either a paralytic or a nonparalytic infection due to any of the three virus types would thereafter be immune to only a virus of the same type.

But later in life, he could contract polio again when exposed to either of the two remaining types of this virus. For this reason, two paralytic attacks could occur in the same individual. Also for this reason, older persons who may have previously been exposed to one or two types, but not all three, were susceptible to the disease. Thus, for complete immunity, it was necessary that there be immunity to all three types of the virus.

The polio virus, which gains access to the body through the mouth or nose, may be transported to the vital nerve centers by the blood stream. The blood of animals, or men, after recovery from an attack, contains a substance called an antibody, which, when injected at the proper time into a susceptible animal, can prevent virus of the same type from reaching the cells of the spinal chord and brain. The prevention of paralysis in this way was first demonstrated in laboratory animals.

Gamma Globulin Used

Then, during the summer of 1952, it was shown that resistance to the naturally occurring disease could be conferred upon children for a brief period by the injection of protective antibodies containing gamma globulin fraction from human blood.

A vaccine is composed of the virus that causes the disease. When the vaccine is injected, the body reacts with the formation of antibodies. These form in the blood and remain to defend against future attacks. Of course, the virus in the vaccine must be rendered harmless so that it won’t be the cause of the disease in the person getting the shots.

In order to prepare such a vaccine, an adequate supply of the viruses must be obtained. Prior to six years ago, the only source of virus for such purposes was the spinal chord of paralyzed monkeys. Then Mr. John F. Enders and his associates in Boston discovered that all three types of polio virus could be propagated in test tubes containing living tissue. This is the principle involved in the current production of the vaccine.

Immunizing Agent Sought

The next problem was to convert those raw materials, themselves potentially hazardous, into a harmless, yet effective, immunizing agent. This was possible by chemical treatment of the virus in the fluid derived from the tissue culture tube.

A mixture for enhancing the antibody-producing power of the virus had to be found that would not result in undesirable side effects. This has already been done in connection with studies carried out in developing a more effective vaccine for influenza.

These are the steps which have lead to the conquest of the crippling disease. But the work has not stopped. Even though the laboratory at Pitt has produced the most potent vaccine to date and has shown the way to bulk production of the virus, Dr. Salk and his team will continue in their quest for a more powerful vaccine.

Read current article: Vaccine immediately cut polio in States