Wednesday, May 14, 2008

vaccines and autism

CBS interviewed Dr. Healy, and now seems to think this is an 'Open Question'. From the interview,
"why in the past decade hasn't the government compared the autism/ADD rate of unvaccinated children with that of vaccinated children?"

Because this has been done before, many times. No link between vaccination and autism has yet been found.
From an article in the Guardian:
"The Danish Epidemiology Science Centre compared 440,000 children who had MMR with 97,000 children who didn't. The children who had MMR were no more likely to develop autism than the children who didn't. A group in London looked at 498 children with autism, to see if they developed it after MMR. They looked at when they had the MMR jab, and when they developed the symptoms or the diagnosis, and found no sudden blip after immunisation. Another paper shows no increase in GP consultations in the six months after immunisation. Two hundred children in London and Stafford with autism were studied to see if there was a new type of autism related to MMR, featuring bowel problems and sudden regression, a bit like in the drama: half had the jab, half didn't, and there was no difference in type of autism between the groups. In California, looking at 1,000 children a year, over 14 years, the number of cases of autism increased by 373%, while the number of children getting MMR increased by only 14% (from 72% to 82%). "

If anyone has published studies showing evidence of a link, I'd surely like to see it.

From the interview again,
"If we can screen children to see which ones might be more susceptible to vaccine side effects.."
There is no known theory and no plausible biological mechanism for vaccinations to cause autism. So how could this screening be done ?
At one point thimerosal was postulated as a possible link. That's a separate discussion, but irrelevant now: child vaccines containing thimerosal are no longer used. Since then, there hasn't been any new causation mechanism proposed.

Also, a study in Japan, published in New Scientist print edition, 17 February 2001:
Journal reference: Journal of Child Psychology and Psychiatry (DOI: 10.1111.j.1469-7610.2005.01425.x)
"They found that the number of children with autism continued to rise after the MMR vaccine was replaced with single-shot vaccines. The medical records of 31,426 children in the city of Yokohama were checked. Before the vaccine was withdrawn, between 48 and 86 children per 10,000 were diagnosed as autistic. After the vaccine was withdrawn, 97 to 161 children per 10,000 were diagnosed with the condition."

There is considerable evidence that the "increase" in autism rates is an artifact of better diagnosis. See the Journal of Pediatrics, and the British Medical Journal.

If you want scary, contemplate thousands of children in iron lungs with polio, thousands of children blind or brain-damaged by measles, epidemics of whooping cough and thousands dying, malformed babies due to their mothers being exposed to rubella, etcetera. This is a certain result of large-scale refusal of vaccinations for populations at risk.

While Dr. Healy has undoubtedly done a lot of good work in the world, I suspect there may be a political aspect to this. Note that Dr. Healy is a Republican political appointee, and was "a member of the Advisory board of The Advancement of Sound Science Coalition, an organization later shown to have been founded by PR firm APCO and funded by the Phillip Morris corporation to criticise scientific research inimical to the interests of tobacco companies and other corporations" (Wikipedia). I don't see what advantage there is to starting this particular hare again, but I suspect it's there. It may just be part of the broader front in the Republican war on science.

The benefits of vaccination are proven. The hypothesis of a link between vaccination and autism is speculative and has no theoretical or evidentiary support. That doesn't mean it does not exist, only that it's unlikely in the extreme. From a public health perspective, investing in studies of a speculative unsubstantiated hypothesis is not easily justified.

Update September 2008: hm, now it appears Lance Armstrong is going anti-vaccine. Science saved his life and career, but now he's joining the druids, the forces of old night and chaos.
Further reading on the subject, rather better-informed than my brief jog through it, here and elsewhere on the site. Predictably, measles is first to make a comeback, but the other horsemen aren't far behind.
Some measurements of the number of lives saved by vaccines is at

More on the horrorshow that preceded immunizations at Making Light.

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Andrew said...
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