Vaccination just may be the most significant medical advance in history. It is difficult to estimate the number of lives saved, but it is in the many millions, to say nothing of the countless number of people who have been spared the misery of mumps, measles, whooping cough and polio. Cases of whooping cough in North America have declined from a pre-vaccination peak rate of about 300,000 per year to 10,000. Measles from a million cases a year to a hundred. Diphtheria and polio are almost nonexistent today in developed countries. How can there be an issue here? How can some parents choose not to vaccinate their children?
The answer likely lies in a growing distrust of the “medical establishment,” a discredited but widely publicized scientific study, inaccurate information being spread on the Internet, and a lack of understanding of the difference between an association and a cause-and-effect relationship. There is no denying that immunization does come with some risk. Rashes, joint pain and fever are well documented, as are occasional lapses in the speed with which safety issues concerning vaccines have been addressed. Oral polio vaccines, which were more convenient to administer than the injected form, were responsible for actually causing the disease in rare cases.
Vaccines, in a sense, are becoming victims of their own success. As memories fade of the horrors of the original diseases that they prevent, more attention is being focused on possible harmful side effects. Instead of having to be concerned about millions dying from smallpox or coming down with measles or whooping cough, we worry about the possibility of vaccination being linked with some cases of autism. That suggestion was raised in 1998 by a paper published in the British medical journal The Lancet. Andrew Wakefield and twelve colleagues claimed that the measles, mumps and rubella vaccine (MMR) caused a bowel disease that then caused autism.
The report received extensive publicity and triggered public demonstrations against mandatory vaccination. Most scientists were skeptical of the Wakefield study, and their skepticism was borne out by the results of an investigation published in 2002 in the New England Journal of Medicine. Danish researchers had examined immunization records and autism diagnoses for all children born between 1991 and 1998 and found that unvaccinated children were just as likely to be diagnosed with autism as those who had received immunizations.
The Lancet study was further discredited when it was revealed that Wakefield had failed to disclose he had received a large grant from a group of lawyers who were looking for ammunition in a lawsuit against vaccine manufacturers. In the end, ten of Wakefield’s co-authors retracted their support for the original research, saying that in retrospect the results as reported were not valid.
The fact is that autism commonly shows up at roughly the same age that vaccines are given, and an association can readily be mistaken for a cause-and effect relationship. But even if there really were a link between autism and vaccination, the anti-vaccine movement would still not be justified. The benefits overwhelm the risks.
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Excerpted from Science, Sense and Nonsense Copyright © 2009 by Dr. Joe Schwarcz. Excerpted by permission of Doubleday Canada, a division of Random House of Canada Limited. All rights reserved.