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Thursday, May 2, 2013

Autism and gut bacteria: The vax. Er, the facts.

When you do an internet search for "autism" and "vaccine", you open the can of worms that was the claim that MMR vaccines caused autism. That fraudulent research and the scientist behind it, Andrew Wakefield, have now been discredited. (For more on that, see the dedicated chapter in the book "Bad Science" by M.D. and writer Ben Goldacre.)

But lately in the news, we came across the words "autism" and "vaccine" in the same sentence again. As in these headlines:

Vaccine developed at U of G could help in battle against autism

Vaccine developed to fight gut bacteria and autism symptoms

First vaccine against autism-associated bacterium Clostridium bolteae

Just how did those two words end up together again? It piqued my interest.

The word vaccine is particularly suggestive. Because what we do know about the cause of autism is this:

(1) There is definitely a genetic component
(2) There may be an environmental component, but scientists don't agree on what it is

A vaccine would not address genes, of course. It would address one of the environmental components thought to cause the condition. But... hold on, if we're not sure what the environmental causes are, how can we take a vaccine and say it addresses that environmental cause?

With that question in mind, I approached this research, which came from the chemistry lab of Dr. Mario Monteiro at the University of Guelph.

I took the step (as always) of reading through the original research paper in the journal Vaccine (in press as of early May, 2013).  That was clearly one more step than some of the reporters who produced articles on the topic (bless their time-strapped hearts). See, anyone who said there was a vaccine obviously didn't read or understand the paper. Because in the article, there is no vaccine.

Here's what's in the paper:

A team of chemists has examined the cell walls of a kind of bacteria (Clostridium bolteae), and have determined that the bacteria can provoke an immune reaction in rabbits.

That is all.

The researchers say their knowledge could be used to develop a vaccine for human use (i.e. they now have a vaccine target), but they did not yet create the vaccine themselves.

Moreover, the facts in this article are padded with the stuff about autism that, given the context, seems absurdly off topic. They took their discovery of making the immune system of rabbits react to a bacteria, and they said, "Hey, some children with autism also have this bacteria in their guts. Maybe we could develop a vaccine against this bacteria and give it to them. And the bacteria would go away. And maybe so would their autistic behaviours."

To me, the paper is about developing a knowledge about a species of bacteria. At most, the discussion section should have mentioned that this particular bacteria may be found in the digestive tracts of some children with autism.

There is no scientific consensus that C. bolteae is unique to the guts of children with autism. Some studies have been done comparing the bacteria in the guts of children with autism to that in non-autistic children, and even though some patterns are emerging, there are no bacteria that reliably distinguish one group from the other. This species of bacteria alone is surely not the "environmental cause of autism" that has been eluding scientists for decades. The researchers do make a case for why they chose C. bolteae, but to me their choice seems questionable, given the conclusions of the papers they cite.

Now, I do think that the connection between autism and gut bacteria warrants more research. (See this episode of David Suzuki's TV show, The Nature of Things.) I'm not dismissing it wholesale. It's just that this paper goes beyond what the evidence shows - both in the peer-reviewed journal and in the media.

The upshot (pun intended...): the word "autism" should not be appearing with the word "vaccine" here at all. That's because the word "autism" should not appear at all, and the vaccine is still a dream. The headlines should read something like:

"Scientists may develop vaccine against species of bacteria with unknown importance".

Only, then they wouldn't be headlines. Hmm, see?? Pequegnat, B., Sagermann, M., Valliani, M., Toh, M., Chow, H., Allen-Vercoe, E., & Monteiro, M. (2013). A vaccine and diagnostic target for Clostridium bolteae, an autism-associated bacterium Vaccine DOI: 10.1016/j.vaccine.2013.04.018