The Vaccination-Autism Connection Debate

Learning to be a father means learning about the ins-and-outs of politics and science that I didn’t really care too much about before.

From Samantha Celera @ Flickr, under Creative Commons

Like everyone, I have been hammered over the head repeatedly with H1N1 hubbub. Canadians are so bored by it that half of them apparently don’t even want the vaccine anymore. However the most recent issue of Wired magazine contains a feature article about a different vaccine controversy: the reputed connection between increasing rates of autism and child vaccination.

Specifically, advocates for a connection between autism and vaccination point to the presence of a chemical used as a preservative in vaccines called thiomersal/thimerosal. An introduction to this controversy is available at wikipedia.

In particular, thimerosal includes a compound called ethylmercury, which as its name suggests, does contain mercury. Odd as it might sound, there is apparently a small amount of mercury present in thimerosal-preserved vaccines.

And what’s this preservative for anyway? Apparently many vaccines are shipped in vials that contain multiple doses, for multiple patients, which means sticking a needle into multiple arms and back into the vial multiple times. This allows for the transfer of bacteria from human to vaccine vial and onward to another human. Apparently thimerosal helps eliminate the bacteria. Therefore we shouldn’t be too surprised to find out that thimerosal is potentially toxic.

Several celebrities have promoted the theoretical connection between childhood immunization and a subsequent onset of autism spectrum disorder, including Jenny McCarthy (who appeared on Oprah) and Robert F. Kennedy Jr (whose article, Deadly Immunity, appeared in Rolling Stone).

Kennedy’s article in 2005 sparked a crossover of the controversy into mainstream. In it, Kennedy quotes Mark Blaxill, member of a nonprofit organization concerned about the role of mercury in medicines, as suggesting: “The damage caused by vaccine exposure is massive. It’s bigger than asbestos, bigger than tobacco, bigger than anything you’ve ever seen.” No small claim.

His article is well-crafted. It implies much with its language, but substantiates little. For instance, this baffling sentence: “In 1930, the company tested thimerosal by administering it to twenty-two patients with terminal meningitis, all of whom died within weeks of being injected.” I’m not MD by far, but I suspect that having terminal meningitis might be a contributing factor to those patients’ deaths.

The crux of the argument relies upon skyrocketing autism rates in the United States since 1991 and the effective doubling of vaccinations in children under six in the years after 1989. The graphs imply correlation. But no one has yet established causation or any direct connection between the two at all. One could easily blame the increased vaccinations for the growth of reality television (cue the pirates please, FSM).

However, I came across one recent Canadian epidemiological study found the reverse to be true. It concluded that “the prevalence of pervasive developmental disorder in thimerosal-free birth cohorts was significantly higher than that in thimerosal-exposed cohorts (82.7 of 10000 vs 59.5 of 10000)” (Pervasive Developmental Disorders in Montreal, Quebec, Canada: Prevalence and Links With Immunizations, PEDIATRICS Vol. 118 No. 1 July 2006, pp. e139-e150).

In spite of the fact that thimerosal has been, or is being, removed from children’s vaccines, the debate remains relevant since it has acted as a catalyst for a dramatic decrease in public support for childhood vaccination. As the Wired article states – and recent polls in Canada suggest – people no longer trust vaccinations: they don’t understand them and they don’t understand the risks associated with vaccination or those associated with the choice not to vaccinate.

Wired author, Amy Wallace, suggests this is a centuries-old struggle: “Looking back over human history, rationality has been the anomaly. Being rational takes work, education, and a sober determination to avoid making hasty inferences, even when they appear to make perfect sense.”

Vaccines will cease to be effective if too few in the general population choose to get them. In an insidious mix of the vaccinated and un-vaccinated, disease can change, surviving long enough among the unvaccinated populace in order to mutate sufficiently to defeat the vaccine itself.

How will this one new dad fair in the war for rationality?

I’ve decided to get the H1N1 vaccine when it comes time. Not for myself. Not for society. But for my wife and the baby.

Everything considered, it seems like the rational choice.

Other Resources:

Andre Picard article in Globe & Mail

CTV article from 2008

A 2004 Pediatrics (Official Journal of the American Academic of Pediatrics) article: “Thimerosal-Containing Vaccines and Autistic Spectrum Disorder: A Critical Review of Published Original Data

UPDATED 27 Nov 09:

I got the shot. So has J. So far so good.

Interesting graphic I found:

5 thoughts on “The Vaccination-Autism Connection Debate

  1. Good call on getting the vaccination.

    I know it’s hard on parents to have a child with autism and many of them are looking for something to blame (because if they don’t then they blame themselves), including Dr. McCarthy. I recently read (possibly on that there are regions that, since they are abstaining from certain vaccinations, some diseases have made a comeback to pre-vaccination rates, which if I’m not mistaken, would likely cause more deaths than cases of autism if the children were vaccinated.

    If you’re worried about mercury, how about compact fluorescent bulbs, or better yet, coal-fuelled power plants? A coal power plant exposes a person to way more mercury than a vaccine would.

    I think the biggest thing is that we don’t know what causes autism and people are looking for something to blame and vaccinations are an easy target.


  2. Although mention of Guillain-Barre and flu vaccination does make me nervous, I agree that the benefits likely outweigh the risks.

    Maybe I’m biased because I never got to meet the aunt that died at age six from Diphtheria. I can’t imagine losing a six-year-old. That’s my son, next year.


  3. Thought provoking & extremely well written. Thanks for the great post 🙂

    As for the arguments presented, I completely agree with you. People naturally fear what they do not understand, and something as vague/complex as disease vaccination will only increase the skepticism of its effects.

    At its core, vaccination is a numbers game. If you can improve the quality of your (not to mention your family’s) life by a small margin, doesn’t that offset the minute chance of it having a undocumented side-effect? As stated – it is the rational thing to do.


  4. Thanks folks.

    Here a Don Martin column from yesterday’s National Post about the Canadian public’s reluctance to get the H1N1 vaccine:

    He mentions briefly the conspiracy theory about autism & vaccinations.


  5. Very well put Robin. It’s times like this that I wish there was a Parenting for Dummies book. It’s a difficult decision when ones faith in the medical system has been shaken (as mine has)- and we are struggling to decide what to do. I know we have decided to get the kids vaccinated, however by the time it’s available it may be too late- thereby shaking my faith in our medical system further! (sigh)
    Welcome to the world of parenting!


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