The National Post
This Vaccine Won't Hurt at All
by Howard Fienberg
No correlation can be found between autism and getting a measles shot
We often find it difficult to balance abstract risks to our health, but if a reliable vaccine for a deadly disease is readily available, shouldn't immunizing our children be an easy choice? Unfortunately, many parents are more frightened of vaccines than the diseases themselves. The sudden measles alert on the campus of McMaster University demonstrates the effects of such misguided fears -- needless cases of potentially deadly diseases.
Many parents fear the vaccine against measles, mumps and rubella (MMR). They see autism develop in children soon after the vaccinations and a dramatic increase in general autism incidence. But scientific evidence hints at no link between MMR vaccinations and autism. Indeed, a new epidemiological study of California, published in the Journal of the American Medical Association, could find no correlation (let alone causation). In their misguided battle against childhood vaccinations, opponents not only fail to save children from autism, they also increase the risk of outbreaks of deadly diseases.
Are rates of autism increasing? Two large population-based studies in the United States, both in the 1980s, found rates of 3.3 and 1.2 per 10,000 children. More recently, the U.S. Department of Education showed the number of children provided with special education service for autism rose from 1991 to 1997 by 556%. The California study saw a relative increase of 373% between 1980 and 1994, from 44 cases per 100,000 live births to 208 cases per 100,000 live births. So it is possible the rates of autism are increasing, but the data are confounded by a broadening of case definition as well as improvements in diagnosis. Autism is less likely to be misdiagnosed or ignored and milder cases are being considered autism than in the past.
Whether or not consensus on autism's rise exists, no epidemiological correlation can be found between the disease and the MMR vaccine. The new California study discovered that the 373% relative increase in autism coincided with a relative increase of only 14% in immunization coverage over the same time period. In England, a 1999 study in The Lancet indicated that their rise in incidence began in 1979, and the data showed no significant jump after the introduction of the MMR vaccine in 1998.
The first widely hailed "evidence" of the supposed autism-vaccine link only arrived in February, 1998, with publication of a study by Andrew Wakefield in The Lancet. Wakefield and his co-authors concluded the MMR vaccine might have caused a bowel disease, which might in turn have caused autism. But that was pure speculation, based on a collection of 12 patients. Four of those cases developed behavioural problems before any symptoms of bowel disease developed. In addition, the link between the measles virus and Crohn's disease, made by Wakefield and his colleagues back in 1994, has since been discredited. It would therefore be unwise to link the MMR vaccine to bowel disease, let alone autism, on the basis of Wakefield's lone evidence.
What is beyond doubt, however, is that serious and deadly disease epidemics would result if we rejected the MMR vaccine. Measles, the concern in Hamilton, is often considered the most threatening. Dr. Tina Iyama, associate professor of pediatrics at the University of Wisconsin-Madison, worries that, having been safe so long, "people forget what measles encephalitis is like." Measles cases overall dropped 98% upon the introduction of a measles vaccine in the United States in 1963. But a resurgent outbreak in 1989-91 is a stark reminder that these diseases are not mere "nuisances." It struck 55,622 people, mostly children under five, resulting in more than 11,000 hospitalizations and killing 125 sufferers. The U.S. Centers for Disease Control and Prevention blamed poor vaccination coverage.
Because they love and care for their children, parents have always been vulnerable to health scares. Intentional or not, drumming up hysteria without reasonable supporting evidence unfairly plays on parental fears, blinding parents to the real risks they and their children face. For parents to make an informed choice, they need to understand both the vaguely possible risks in administering the vaccine and the concrete probable risks in withholding it. While avoiding the MMR vaccine is unlikely to prevent autism, such action makes the recurrence of epidemic diseases such as measles or rubella more likely. As the alert in Hamilton has shown us, that is no trivial matter.
Howard Fienberg, a Canadian, is research analyst at the Statistical Assessment Service, a nonprofit nonpartisan think- tank in Washington, D.C.
(see the original article at http://www.nationalpost.com/commentary/story.html?f=/stories/20010322/508869.html )
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