Syringe containing childhood vaccineTwo new studies published this month are suggestive of a link between autism and both vaccinations and poisoning with mercury and other heavy metals.

Following the retraction by The Lancet of Dr. Andrew Wakefield's paper linking the Measles-Mumps-Rubella (MMR) vaccine with autism five months ago many may have assumed the case was closed but these new studies provide compelling evidence that further investigation in this area is required as the science increasingly points to environmental factors interacting with genetic predisposition in the development of autism. 

The first study was conducted by researchers at the University of Pittsburgh in cooperation with Thoughtful House, an Austin, Texas autism research and treatment centre. The group found that vaccinated baby macaques (monkeys) shared several traits with autistic children, while their unvaccinated counterparts developed normally.

Animal studies of course do not provide definitive proof of a link between vaccines and autism in humans but primates and humans do share a very similar genetic makeup making the chances of a similar reaction fairly high. It is difficult to conduct studies of this kind on human infants for ethical reasons as one group would have to remain unvaccinated which would leave them open to contracting potentially serious infectious diseases. Health agencies including the Centers for Disease Control and Prevention (CDC), Food and Drug Administration (FDA) and National Institutes of Health (NIH) often rely on animal data to determine drug safety for similar ethical reasons. SafeMinds, a non-profit organisation that promotes research and action against mercury-induced neurological disorders part funded the study due to their concerns that mercury-based vaccine preservatives such as thimerosal are a causal factor in autism.

The second study provides more compelling evidence of an association between heavy metal toxicity and autism and was conducted independently by scientists from the University of Iowa with no involvement from autism organisations. This study was a review of existing published research investigating an association between heavy metal toxicity and autism. Such reviews are considered the best form of scientific evidence in medicine if conducted properly as they draw conclusions from a large body of research on a specific subject.

The University of Iowa team looked at a total of 58 studies. Of these 43 showed that there was evidence for a link between autism and heavy metal poisoning, while only 13 showed no indication of such a link. While it cannot be ruled out that children with autism could be predisposed to have an unrelated metabolic disorder that inhibits their ability to detoxify heavy metals and safely excrete them from their bodies, the study provides sufficient evidence to support calls for further research in this area as advocated by SafeMinds and a number of other autism advocacy groups.

To limit a child's exposure to mercury and other toxic metals SafeMinds recommends limiting limiting fish consumption (a major source of mercury) and researching the ingredients in your child’s vaccinations. The limiting of fish consumption is already widely advocated by health authorities and family physicians worldwide.

Both studies were published in the journal Acta Neurobiologiae Experimentalis earlier this month.



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