19 October 2005

Vaccine-autism nexus denied (again)

The article Vaccine-autism nexus denied reports on the conclusions by the Cochrane Collaboration of a "scientific review of 31 select studies" into a connection between the MMR vaccine and autism (and other disorders):

'We found no evidence that giving MMR causes Crohn's disease and/or autism in the children that get the MMR,' said Tom Jefferson, one of the authors of The Cochrane review. 'That does not mean it doesn't cause it. It means we could find no evidence of it.'
The responses from the two sides were, as I think we have all come to expect, drawn along "party lines".
[PRO] At the same time, he said, 'We don't think there is any point in further investigating the association. ... The controversy should be put to bed.'

[CON] Many parents and advocates for children with autism have been reluctant to accept the conclusions of such studies, and advocates continue to call for more research.... 'It may be hard to prove that autism is caused by an injection, but all vaccinations have side effects, and the report can't ignore that,' said Debora Harris of the Elija Foundation, a nonprofit serving Long Island caregivers, parents and teachers of children with autism. 'I know a lot of parents who were holding their child in their arms a few days after the vaccination and seeing changes in their child.'
Obviously, the side that contends there is no link is happy with these results and will undoubtedly add it to their arsenal of justification. On the other hand, those who contend that there is a link will find ways to discredit this study, or the ones it is based on, and push for continued, valid research to find the link.

Barbara Loe Fisher, co-founder and president of the National Vaccine Information Center, probably says it best (as quoted in the story):
"This is not going to put the issue to rest," she said. "When the experience people have with vaccines is different from what the government and vaccine manufacturers are saying, you are not going to put this to rest."
It seems to me that there are two major challenges in, as Fisher puts it, putting this to rest - 1) designing a valid research program, and 2) implementing that program. I'm not sure which would be harder.

The Cochrane Review was imperfect / flawed (depending on which side you look at it from) in that it relied primarily on the results of epidemiological and retrospective studies and the comparison of the MMR vaccine with a single measles or rubella vaccine. The problem, as cited in the article, is the difficulty in finding a non-vaccinated control group for comparison. (Perhaps they could use the Amish?)

First things first: Has anyone developed a proposal for a research program that both sides could agree was a valid test of the connection between vaccines and autism? I've done a very cursory search, but haven't had time to really look into this.

UPDATE:

A story from US News and World Report on this research provides even more insight into how poor studies of vaccines are:
There's no credible evidence behind the theory that autism is triggered by the measles-mumps-rubella (MMR) vaccine, scientists have concluded after reviewing 31 studies, many of which they found flawed by unreliable reports of outcomes, incomplete descriptions of the children studied, and other sources of possible bias. And those were the good studies–the researchers tossed out almost 5,000 others with even more blatant defects.

But possible defects contaminated so much of the research that the authors end their report with a scolding for the medical research community, saying that studies were so sloppy they could barely prove MMR vaccines prevented their targeted diseases–although, they are quick to point out, the fact that mass immunization has coincided with mass elimination of these diseases in many, many countries makes it hard to argue that vaccines don't work.
The hypocrisy of the last sentence amazes me. What would the reaction be, I wonder, if the sentence were just slightly reworded:
The fact that mass immunization has coincided with mass increase of autism in many, many countries makes it hard to argue that vaccines don't cause it.

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