Autism, vaccines, and the candidates

Posted by Josh Rosenau on April 22, 2008
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Hilzoy compares three candidate comments on the alleged autism/vaccine link:

Last month I wrote about John McCain’s statement claimed that there is “strong evidence” that thimerosal in vaccines causes autism. I expect better from Democrats, and while saying that we don’t know whether vaccines cause autism is better than saying that they do (or did, while thimerosal was still used), it’s not better enough. And both Democratic candidates have said this. Obama:

“We’ve seen just a skyrocketing autism rate. Some people are suspicious that it’s connected to the vaccines. This person included. The science right now is inconclusive, but we have to research it.”

Clinton answering a questionnaire:

“Would you support a large-scale federal study ofthe differences in health outcomes between vaccinated and unvaccinated groups?

Yes. We don?t know what, if any, kind of link there is between vaccines and autism — but we should find out.”

Stop it. Not vaccinating kids can kill people, and we should not encourage the idea that vaccines are dangerous without good reason. If our candidates don’t know the facts, they shouldn’t pretend that they do.

Hilzoy is right, but leaves out an important nugget from the Obama quote. As her link points out:

Obama campaign spokesman Tommy Vietor has supplied video which suggests that Obama may not have been referring to himself when he said that “some people” were suspicious about a connection between autism and childhood vaccinations. The video shows the candidate pointing to someone in the audience when he adds the words, “This person included.”

So he isn’t backing that claim, just saying that an audience member thinks that. He should have done more to reject that purported link, but that line is the only one where he actually seems to lean toward linking autism and vaccines, and context clarifies that.

I was preparing to write a peeved note to the campaign, but I realized that there isn’t really a hook for that. I could complain about the statement that “The science right now is inconclusive, but we have to research it,” but that line is fairly ambiguous. The topic of the paragraph, after all, is the skyrocketing autism rate, and as I understand it, there’s no well-documented explanation for that. Better detection is part of the explanation, but some studies suggest that that isn’t adequate to explain the whole trend. Which means that the science on the broader topic is, in fact, inconclusive.

It is not inconclusive about vaccines. Vaccines do not cause autism. They save lives. McCain is flatly wrong to say otherwise, as is Hillary. Obama’s statement is ambiguous, and while it would be nice if he were clearer, that’s rather different than McCain and Hillary’s unambiguous wrongness.

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Comments

  1. #1 Orac
    April 22, 2008

    The topic of the paragraph, after all, is the skyrocketing autism rate, and as I understand it, there’s no well-documented explanation for that. Better detection is part of the explanation, but some studies suggest that that isn’t adequate to explain the whole trend. Which means that the science on the broader topic is, in fact, inconclusive.

    Wrong.

    There are a number of studies that show that better recognition, a widening of the diagnostic criteria that occurred 15 years ago, and diagnostic substitution account for virtually the entire apparent increase in autism prevalence and the true rate of autism prevalence is probably not increasing. It is possible that there has been a small increase in the rate, but it’s just not correct to say that the existing science is inconclusive. It’s pretty conclusive. The “autism epidemic” myth is one pillar of antivaccination pseudoscience.

  2. #2 Josh Rosenau
    April 22, 2008

    Ah. Can’t remember where I picked up my sense that there were ongoing questions about whether the rise in autism rates was explained by changes in diagnostics and awareness. I basically only read about autism at your blog, and it was unlikely to be there. Is there any ongoing debate over this point within the medical community, or is this being pushed entirely from outside?

    I note that Wikipedia shares my impression, and cites Newschaffer, et al. (2007), which says “Nonetheless, the question of whether this historical increase can be fully accounted for by these and other changes in diagnosis and classification remains open to debate, largely because it is very difficult to develop quantifiable estimates of diagnostic effects and virtually impossible to prove or disprove temporal changes in autism population risk profiles given the condition’s unknown etiology.”

    I don’t know this field, and I don’t know the authors, so I can’t judge the paper on that criterion. I do know that the Annual Reviews series is well-respected in fields I’m more familiar with, and am inclined to place some stock in what it says.

    Partly because I obviously share Obama’s (mis)impression, I’m inclined to think this is a different category of misstatement than claiming that there’s any evidence of a link between vaccines and autism, which Obama did not do.

    I’d also point out that vaccines are far from the only plausible environmental factor which could influence autism rates, so attributing the claim that there’s an autism epidemic only to antivaxers seems to paint with a needlessly broad brush. I have no dog in this fight, and would obviously rather think that autism is not on the rise. My questions are motivated only by inexperience with this field, and curiosity about the data.

  3. #3 Orac
    April 22, 2008

    I’d also point out that vaccines are far from the only plausible environmental factor which could influence autism rates, so attributing the claim that there’s an autism epidemic only to antivaxers seems to paint with a needlessly broad brush.

    I hope you misspoke. Vaccines never were a particularly credible environmental factor. The reason vaccines were blamed is nothing more than a post hoc fallacy and confusing correlation with causation because around 20% of cases of autism are diagnosed between 1-2 years of age, which is when children are receiving many of their vaccines.

    As for other environmental causes, the problem is that antivaxers really have taken over the claim and run with it to the point that they risk discrediting legitimate science looking at such issues. In any case, the most recent research suggests a strong genetic component to autism.

  4. #4 Josh Rosenau
    April 23, 2008

    D’oh! Yes, vaccines are not and were never a plausible explanation.

  5. #5 hjr
    April 23, 2008

    Now I understand why the candidates all declined to participate in a Science Debate in Philadelphia. Ignorance of the subject.