One of the most comprehensive studies of the link between vaccinations and the preservatives in them and autism was published last year in the New England Journal of Medicine. Titled "A Population-Based Study of Measles, Mumps and Rubella Vaccination and Autism," authors Kreesten Meldgaard etal found there to be no link between the Thimerosal in vaccination preparations and autism. This piece of research is certainly a compelling argument against any connection; it is perhaps not, however, the final word on the subject that its authors argue it to be. While its findings are sound, they are limited to the MMR vaccine; this is not the only vaccine that can contain Thimerosal.
This paper is based upon epidemiological research rather than biological research; in other words, it is a correlation study between vaccination type, timing and the onset of autism vis-a-vis "standard" rates of autism. This alone makes one part of the case against a connection between autism and vaccination. Other research based not on post-facto epidemiological studies but rather on the biology of autism (and in general of auto-immune syndromes) must be considered as well.
Other researchers have investigated this aspect of a possible connection between vaccinations and autism and have again found that there is no link between the biology of autism and mercury as a trigger (although heavy metals are triggers for some types of auto-immune responses. For example, Trottier et al. (1999) found that rather than environmental triggers (which would include vaccinations), the primary cause for autism appears to be genetic. (Their work did not exclude the possibility that environment factors might not trigger autism in a genetically susceptible individual, but found no evidence that Thimerosal was one of these triggers.) They concluded that there is certainly a biological element to autism and one that is linked to inheritance, but that environment may also play a role. (This is hardly surprising; nearly every disease is affected by both genetic and environmental factors).
In summary, the prevailing view is that autism is caused by a pathophysiologic process arising from the interaction of an early environmental insult and a genetic predisposition (p. 115).
Comi etal (1999) found the same concatenation of environmental and genetic factors to be at play in the onset of autism.
An increased number of autoimmune disorders [in patients' families] suggests that in some families with autism, immune dysfunction could interact with various environmental factors to play a role in autism pathogenesis." (Comi etal, 1999, p. 394).
Other research (Barak etal, 1998) have found that the trigger for autism may well be viral infections of the central nervous systems. (The authors also found a genetic propensity for such viral infections; thus the picture presented in this case between environmental influences and genetic ones vis-a-vis autism becomes even more complex.) large amount of research into autism has in fact found links between the onset of autism and either other viral infections as well as the onset of autism and a variety of auto-immune conditions. Kiln (1998), for example, found a correlated between autism and inflammatory bowel disease.
In summary, there is no known connection between autism and the Thimerosal in vaccines, although the exact etiology of autism remains unknown, although it is generally agreed to derive from both environmental and genetic factors.
Barak, Y., etal. (Spring 1998). "Autistic subjects with comorbid epilepsy: a possible association with viral infections." Child Psychiatry and Human Development 29 (3): 245-51
Comi, A.M. et al. (June 1999). "Familial clustering of autoimmune disorders and evaluation of medical risk factors in autism." Journal of Child Neurology 14 (6): 388-94. http://www.fda.gov/cber/vaccine/thimerosal.htm#thi
Kiln, M.R. (May 1998), "Autism, inflammatory bowel disease, and MMR vaccine." Lancet 351 (9112): 1358.
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Trottier et al., (March 1999). "Etiology of infantile autism: a review of recent advances in genetic and neurobiological research" Journal of…