This article archived by August 2007


This article was written by Christopher Kent, D.C., FCCI and appeared in the March 2000 issue of The Chiropractic Journal:

When questions of vaccine efficacy have arisen, I've often been asked, "But what about polio? I remember the braces, the iron lungs, the crippled children. They disappeared after the Salk vaccine." The error is confusing correlation with cause and effect. The incidence of polio was decreasing before the Salk vaccine was administered. Following the administration of the Salk vaccine, there was an increase in the number of polio cases, followed by a continuation of the natural decline that pre-dated the vaccine. Proponents of polio vaccine conveniently ignore previous polio epidemics, where the disease all but disappeared in the absence of a vaccine.

Let's look at some polio statistics. In 1942, the epidemic of the first half of the century subsided, and there were fewer than 5,000 cases of polio in the United States. Around 1948, the number of polio cases began to soar. Interestingly, this is about the time the pertussis vaccine appeared on the public health scene. Polio reached a high in 1949, and then began its natural decline. In 1949 there were nearly 43,000 cases of polio. By 1951 the number had dropped to below 28,000. Following a government-subsidized study of polio vaccine, the number soared to an all-time high of more than 55,000 cases. A "bad batch" of vaccine produced by Cutter Laboratories was deemed the cause of many cases of polio. Fortunately, better quality control procedures governing the inactivation of the virus were initiated, and the number of cases continued to decline. Of course, the vaccine got the credit -- not nature.

An even more interesting abuse of statistics becomes apparent when perusing polio statistics. The diagnostic criteria and reporting procedures for the disease changed. In the 1950s, the sophisticated virological techniques of today did not exist. And the technology that existed was rarely available to practicing physicians. Therefore, most diagnoses were based upon clinical observation, not sophisticated virological studies. Since polio was epidemic, most physicians were cavalier in making a diagnosis of "non-paralytic poliomyelitis" in children presenting with vague symptoms of muscle aches, malaise, and fever. Since polio was "going around", such children must have had polio. Today, they might be diagnosed as having influenza, again in the absence of laboratory confirmation. And like influenza today, most cases of polio were self-limited. The cases progressing to the paralytic form got the publicity.

Interestingly, as the number of polio cases decreased, the number of meningitis cases increased. Consider these figures from the Los Angeles County Health Index: Morbidity and Mortality, Reportable Diseases (listed here by date, followed by number of cases of a)viral or aseptic meningitis, b)polio):
- Jul 1955 a)50 b)273
- Jul 1961 a)161 b)65
- Jul 1963 a)151 b)31
- Sep 1966 a)256 b)5 (5 year median)
- Oct 1966 a)312 b)3

The authors of this publication offer an explanation for this rather strange inversion of figures: "Most cases reported prior to July 1, 1958 as non-paralytic poliomyelitis are now reported as viral or aseptic meningitis." In another masterful example of faulty reasoning, it was concluded that since the vaccine had "wiped out polio", children with similar symptoms must have something else -- meningitis!

The polio vaccine developed by Jonas Salk was a killed virus vaccine. The oral polio vaccine developed by Albert Sabin and until recently used routinely in the United States, is a live virus vaccine. Public health authorities acknowledge the fact the it can and does produce paralytic polio in a small number of recipients. Yet, they promoted it over the safer Salk vaccine because it is easier to "sell" parents on a one-time regimen of an oral vaccine over an injected vaccine where "booster" doses are recommended. The oral vaccine is also said to confer "herd immunity". Vaccine recipients infect unvaccinated persons, thus increasing the immunity of the "herd".

What is the risk of contracting naturally occurring polio? According to Jonas Salk, the current live virus polio vaccine developed by Dr. Albert Sabin was "the principal if not the sole cause of the 140 vaccine cases reported in the U.S. since 1961. At the present time the risk of acquiring polio from the live virus vaccine is greater than from naturally occurring viruses."

In summary:
1)The number of polio cases was declining before the widespread administration of the Salk vaccine.
2)Cases which had previously been reported as polio are now reported as meningitis.
3)The risk of contracting polio from the live virus vaccine is greater than the risk of acquiring the disease from naturally occurring viruses.

Today, medical authorities are recommending a return to the injectable Salk vaccine. However, the live virus Sabin vaccine will probably still be used in developing countries.

A chilling legacy of the live polio vaccine may be the virus associated with AIDS. Edward Hooper's book "The River: A Journey to the Source of HIV and AIDS" suggests that AIDS may be the result of a live virus polio vaccine administered in Africa in the 1950s. According to Hooper, the vaccine may have been contaminated with a simian (monkey) virus. This virus is thought to have evolved into the HIV virus.

Although the theory is controversial, it demonstrates how the potential risk of vaccines may not become evident until decades after their administration.


1. Kent C, Gentempo P: "Immunizations: fact, myth, and speculation." International Review of Chiropractic. November/December 1990.
2. Hooper, E: "The River: A Journey to the Source of HIV and AIDS." New York. Little, Brown and Company. 1999.