Archives | (January 2002) Printer Friendly
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The development of the Salk polio vaccine has been called one of the greatest medical achievements of the century. Today, however, there is growing fear that early stocks of the vaccine may also have contained a ticking time bomb that holds the seeds of a new and frightening epidemic of cancer and autoimmune disease. What is disturbing, though, is the appearance that government officials have withheld information concerning this potential threat from the public for over four decades. Even more disturbing is the fact that the cover-up continues to this day.

During the first half of the 20th century, the word "polio" conjured up visions of paralysis, iron lungs and early death. In 1952, the peak year, the dread disease struck 57,000 Americans and claimed 3,000 lives. Then, a medical miracle occurred. On April 12, 1955 Dr. Jonas Salk announced that he had developed a vaccine that provided protection against poliomyelitis. The same day, the federal government licensed the Salk vaccine for distribution. Salk declined to patent the vaccine saying he had no wish to profit from his discovery and wanted to see it made as widely available as possible. Soon, millions of Americans were being inoculated.

The Salk vaccine was prepared by growing the polio virus on tissue taken from the kidneys of rhesus monkeys. Once harvested, the virus was then "killed" by exposing it to formaldehyde. When someone was injected with a vaccine produced from the "killed" virus, their body would react as though it had been infected and begin producing antibodies to attack the invading disease cells. The advantage of using a "killed" virus in the vaccine is that there was little risk of the recipient actually contracting polio.

Between 1955 and 1961, some 98 million Americans - more than 60% of the population -- were given the Salk vaccine, and the incidence of polio began a dramatic decline. What they did not know, was that when vaccinated, some people got more than just an immunization against polio.

In 1959, Bernice Eddy, a researcher at the National Institutes of Health had made a disturbing discovery. While examining rhesus monkey cells - the same type used to make the Salk vaccine -- under a microscope, she noticed that some were dying without any obvious cause. Concerned, she ran further tests, taking extracts from rhesus monkey kidneys and injecting them into 23 hamsters. Within months, 20 of the 23 test animals had developed "large, malignant subcutaneous tumors."

Alarmed, on July 6, 1960, Eddy went to her boss, Dr. Joseph Smadel and reported her findings. Smadel dismissed the tumors as "lumps." He could not have been more wrong.

At about the same time that Eddy was conducting her experiments, two researchers working for the Merck pharmaceutical company, Drs. Maurice Hilleman and Ben Sweet, had isolated a new virus from kidney tissue of rhesus monkeys. The 40th such virus discovered, it was called SV 40.

In 1961, the new Sabin oral polio vaccine, which used a live virus, was introduced. The Sabin vaccine promised lifelong immunity to both paralysis and infection, and was easier to administer. Eventually, both the Salk and Sabin vaccines would be administered to patients in alternating doses.

But there was a problem.

In the course of routine testing, it was discovered that batches of both the Sabin and Salk vaccines were contaminated with the SV 40 virus. Some estimates indicated that as much as a third of the Salk vaccine that had been administered was tainted. Worse, additional testing had confirmed what Dr. Eddy had feared - that the SV 40 virus was causing cancer in lab animals.

The government moved swiftly to ensure that future batches of polio vaccine were free of the SV 40 virus, but allowed existing stocks to be used. More important, government officials decided not to notify the public of the potential danger out of fear that it would cause panic and interfere with the vaccination campaign. Indeed, the only public mention of the problem was a story buried on page 33 of the New York Times. It said that polio vaccine manufacturers were suspending production to remove a monkey virus from the vaccine. The story also said that the Public Health Service said that the virus was not dangerous - even though there was no basis for such an assertion!

The following year, the National Cancer Institute assigned Dr. Joseph Fraumeni the task of determining whether recipients of the vaccine demonstrated any increase in cancer. He tested samples of the vaccine administered in May and June of 1955 to measure their extent of SV 40 contamination - whether it was high, low or uncontaminated. He then determined where the vaccine had been distributed and examined cancer mortality rates among children who had been vaccinated at that time.

His findings - that there was no significant difference in cancer deaths among children in the states examined regardless of the presence or lack of SV 40 - were published in the Journal of the American Medical Association. That, as far as the federal government was concerned was that. No consideration was given to the fact that there might be a time lag of decades before a virus-related cancer appeared, or that he had selected a relatively narrow sample. His study cleared the way for continuing polio vaccination and that is what the federal medical establishment wanted.

Over the intervening years, however, reports began to surface linking SV 40 to human cancers. As the evidence mounted, Fraumeni decided to take a second look at the issue. This time he selected a group of 1,073 black children who had been given the Sabin oral vaccine in a test conducted at Cleveland Metropolitan General Hospital. It was known that the batch used in this test was contaminated with SV 40. Letters were sent to the vaccine recipients, now young adults aged 17 to 19. Less than half responded. The researchers failed to find evidence of SV 40 related health problems, and so once again, the threat was dismissed. As with the earlier study there were fatal flaws with the 1976-79 review as well.

An analysis of Fraumeni's methodology published in the 1982 New England Journal of Medicine was critical on a number of points. First, it noted that a majority of the vaccine recipients had not responded, greatly limiting the potential validity. Secondly, it noted that the types of cancers associated with SV 40 might easily take more than 17 to 19 years to develop. Finally, and perhaps most important, it noted that it appeared that individuals who were given the Sabin vaccine were much less likely to be infected by the SV 40 virus than those given the Salk vaccine.

Despite these obvious flaws, government officials took the Fraumeni study as more proof that SV 40 was not a threat.

Soon more disturbing data would emerge...

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