Wednesday, June 2, 2010

NBC Dateline: Vaccines and Autism Edition

The other night, Dateline had a special about Andrew Wakefield, the man who started the whole anti-vaccine movement.  In the latest in a string of events that can only be described as the complete discreditation of Dr. Wakefield, the general medical council in the UK has struck his name from their register, a move equivalent to revoking his license to practice medicine.  Dateline did a pretty good job with the issue, and it is worth watching if you aren't too familiar with the supposed "controversy" (you can check it out below).
 I really do think the whole thing is such a shame.  I understand why people want to believe in Wakefield's claims, because he offers hope for an otherwise hopeless situation, and he seems so genuine and sympathetic, I almost want to believe him myself.  But there are 2 things (mainly) that prevent me from taking him at his word...
First, as you can see in the video, there were a few issues with potential conflicts of interest... Wakefield was being paid (about $750,000 U.S.) by lawyers who were bringing a civil case against MMR vaccine manufacturers.  Also, he held a patent for a treatment to be used either in place of MMR, or in children who had an adverse or unsuccessful reaction to MMR.  Thus, it was in Wakefield's financial interests to present a story that MMR was either dangerous in some way, or, ineffective.  Having these financial interests is not necessarily bad in and of itself, but what bothers me is that they were never disclosed... at least not until after they were exposed by Brian Deer's investigative reporting.  All scientific journals have a form you have to fill out if your manuscript has been accepted, and most, if not all of them, ask you to disclose "ANY POTENTIAL conflicts of interest".  In my experience, honest scientists put down anything and everything they think might even be remotely considered a conflict of interest, and they usually list ALL of their sources of funding regardless. Which is why Wakefield's excuse that the lawyers were paying him for another study, and that he used the money for research only doesn't excuse him in my mind.  These things should have been reported initially to the editors of the Lancet, by Wakefield himself, in the interest of transparency and full disclosure.  I believe that any scientist worth his or her salt would do so, and thus, I can't help but to find Wakefield's behavior to be deceitful.  But even if he didn't know better because he was more of a clinician than a researcher, there is a much more convincing reason to disregard Andrew Wakefield's claims, and that is bad science.

This is my second major point of contention, and for me, it is far more important than character issues.  If you take a look at the original paper from the Lancet (now retracted) you can see that there is a very large disconnect from what the study showed and what Wakefield is claiming.  First, Wakefield and his colleagues only examined 12 children, which is a very small sample size for a disease that affects anywhere from 1 in 110 to 1 in 150 children in western countries.  Ignoring the size of the sample, however, there is also a glaring selection bias in this study in that ALL of the children in the experimental group were selected based on the fact that they had been previously diagnosed with autism-like symptoms, AND, they had come to the Royal Free Hospital with gastrointestinal complaints.  After examining the patients for bowel inflammation, the researchers found that the autistic patients, who had been admitted complaining of gastrointestinal symptoms, did have signs of inflammation in the large intestine.  Go figure.  It's kind of like selectively removing all the red M&Ms from a bag of M&Ms, then taking a closer look at them, and concluding that all M&Ms must be red.  And, in fact, the authors of the manuscript say as much in the discussion: "We describe a pattern of colitis and ileal-lymphoidnodular hyperplasia in children with developmental disorders. Intestinal and behavioural pathologies may have occurred together by chance, reflecting a selection bias in a self-referred group..." (emphasis added)
The point is, at the time, this paper presented a small set of observations that suggested an hypothesis that can be paraphrased like this: "swollen lymph nodes, or other inflammatory processes in the intestinal tract may be related to autism pathogenesis".  In fact, that is how the scientific community took it, and since 1998, many studies have disproved this hypothesis (a couple of which can be found here and here).  And since Wakefield tried to extend beyond this hypothesis to implicate vaccines as causing autism, several groups set out to test this idea as well, and it has also been disproved (here and here for just a couple examples).  Ultimately, the problem here is that Wakefield is treating his hypothesis as if it were proven fact, and the end result is that children may not be getting much needed vaccines and Wakefield is exploiting parents of autistic children by selling them snake oil (or a pipe dream) and accepting their money for his books, lectures, etc.
I plan to post a more thorough review of the evidence at some later point, as well as an examination of all of the various permutations of the anti-vax hypotheses (thimerosol, etc.) but for now, here's the Dateline video...

(Click here to watch the whole episode)

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