In defence of vaccinations

AVOID! One of the most common words of advice heard these days. Avoid tap water. Avoid bottled water. Avoid butter. Avoid margarine. Avoid the sun. Avoid sweeteners. Avoid genetically modified foods. Avoid plastic bags. Avoid paper bags. Avoid preservatives. Avoid dairy. Avoid meat. Avoid soy. Avoid’ah, never mind. I could go on and on with a litany of such ‘avoids.’ There are some valid points to be made with some of these, but there is one avoid that I cannot stomach. Advising parents to avoid childhood vaccination is scientifically unjustified and dangerous.

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. I can vouch for the agony of whooping cough myself. Feeling as if you are going to cough your lungs out is a memory that doesn’t leave you easily. I survived, but one of my classmates in grade two did not. And how often can one say that a disease has been completely wiped off the face of the earth by a medical intervention? The last case of smallpox was recorded in 1978. The World Health Organization estimates that smallpox killed as many as 500 million people in the twentieth century and that as recently as 1967 it was responsible for two million annual deaths.

Other vaccines may not have eradicated diseases, but they have curbed their incidence very significantly. 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. The incidence of hepatitis B and tetanus have been reduced by a factor of forty, rubella by two hundred and mumps by four hundred. The effectiveness of immunization is simply beyond argument. How can there be an issue here? How can some parents choose not to vaccinate their children?

It really is a conundrum. But 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. Although we may not think of it in such terms, the decisions we make in life often come down to a risk-benefit analysis. Whether it is flying in airplanes, eating smoked meat, taking cholesterol lowering medication, or vaccination, there are always pluses and minuses to consider. 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. Yet some twenty years were allowed to pass before switching back to the safer, injectable form. An infant vaccine against an intestinal infection that struck roughly four million babies a year in North America was found to cause an increase in life-threatening cases of bowel collapse and had to be abandoned. Although there is no scientific evidence linking the mercury-containing preservative thimerosal to any disease, it probably should have been removed from vaccines more speedily when ill effects attributed to mercury in other contexts became apparent.

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. Indeed, one can judge the progress of society by looking at its worries. 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.

Other studies around the world also refuted the link between vaccines and autism, but a vocal group of anti-vaccine advocates maintains that a witch hunt has been organized against Wakefield to protect vaccination interests. Humbug. 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.

In Britain, the consequences of the vaccine scare are already being seen in rising rates of mumps, rubella and measles. And Britain faces another problem: homeopaths are recommending that tourists travelling to malaria-stricken destinations use homeopathic remedies instead of well-tested prescription prophylaxis. This is ludicrous. Homeopathic products contain no active ingredient of any kind, so it comes as no surprise that a number of travellers have already paid for their folly with their health. Many homeopaths also advise their patients to avoid vaccines in lieu of a cacophony of implausible homeopathic medications. If indeed you are looking for something to avoid, how about this silly and dangerous advice?

What do you think? Share your point of view in the comments.

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.