The number of people who have made confident assertions about thiomersal causing autism over the last four years or so is astounding.
It’s now 2005…..[W]e should see fewer cases entering the system this year than we did last year.– David Kirby
if the total number of 3-5 year olds in the California DDS system has not declined by 2007, that would deal a severe blow to the autism-thimerosal hypothesis…..total cases among 3-5 year olds, not changes in the rate of increase is the right measure.– David Kirby
“Late 2006 should be the first time that rates go down” said Handley. “If they don’t, our. hypothesis will need to be reexamined.”– JB Handley
...I would like to make a virtual wager that within the next 18-24 months scientific evidence will make the thimerosal-autism link a near certainty.– Richard Deth, March 22, 2006.
All these statements have one thing in common, they promote the idea that mercury (thiomersal in particular) causes autism in either all, or the vast majority of cases.
However, listening to the Autism Omnibus yesterday provided a very interesting change from this perspective:
In some kids, there’s enough of it that it sets off this chronic neuroinflammatory pattern that can lead to regressive autism,” said attorney Mike Williams.
ABC.
Note the new language: ‘some kids’....’regressive autism’.....’can lead’.
It seems the days of ‘all autism is mercury poisoning’ are long gone.
Petitioners presented a very interesting expert witness yesterday – a Dr Sander Greenland from UCLA who is a Professor of Epidemiology.
Dr Greenland argued some strange facts for the PSC but completely in line with this new tack that I can’t even remember being argued in the Cedillo hearing (thiomersal may cause regressive autism in some kids).
Greenland essentially argued that all the current epidemiology regarding autism and thiomersal was not good enough to detect thiomersal causation in regressive autism – this is from his submitted report:
A simple example may clarify this point. If a vaccine is not associated with any type of disorder in the category, we should expect to see the same risk when comparing vaccinated to the unvaccinated. Suppose, however, that in reality the vaccine is associated with a two-fold increase in the risk of a type of disorder in the category, but not associated with any other type. Suppose also that, without the vaccine, the associated type represents only one-tenth (10%) of the disease category, and that the total number of cases in the category would be 100. Then, without the vaccine, the number of cases with the associated type would be 100/10 = 10. With the vaccine, however, the number of cases with the associated type would double, to 20, an excess of 10 cases over the original 10 with the associated type. This excess produced by the vaccine would result in a total of 100+10 = 110 cases over the full category, which is only a 10% increase in the risk of any type in the category. Thus, the risk ratio for getting any type in the category would be only 110/100 = 1.1. Such a small risk ratio cannot be reliably distinguished from 1 by ordinary epidemiologic studies.
In other words, the amount of autism caused by vaccines is in fact too small to be detected by epidemiology. If, of course, it is associated with it at all – a point made later by Dr Greenland:
The brief overview given above supports the idea that the association of MCV (mercury containing vaccine) with autism is small or nonexistent.
But really his point is that if thiomersal does cause autism (and whilst he professes to have ‘no opinion’ on the matter it may be telling that he refers to the idea as a hypothesis throughout his report, not a theory) it causes it in very, very small numbers indeed.
Dr Greenland passed no opinion the validity of the hypothesis itself. Rather, he was there to study epidemiology. We have to respect his opinion even if we disagree with it.
The more telling aspect for me was this sudden conversion from ‘vaccines cause autism’ to this suddenly tiny percentage – so small to be undetectable by epidemiology up to this point. That’s quite a step back. What will become of the Omnibus cases that are not considered’ regressive’? Or the ones (like Michelle Cedillo) who were claimed to be regressive but were, upon viewing the video evidence, clearly not. Are the PSC really throwing cases away?
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