As promised here is the first of the articles that I deal with in the formal complaint I made to the Charities Commission regarding the misinformation spread by the anti-vaccine charity IAS.  So, with out further ado (what is ado anyway?) here is the link to the offending piece and my rebuttal:

Thimerosal in your Vaccine?
Posted September 13, 2010

This post on the IAS website (made up of basically an uninformed question about the harmfulness of ethyl mercury and a video) insinuates that Ethyl Mercury (also known under the trade name Thimerosal)1 is both harmful in the amount contained in vaccines and, by extension, that New Zealand vaccines contain this substance and should therefore be viewed with suspicion.

The first thing to note is that the Thimerosal post is irrelevant to New Zealand populations as Thimerosal is not present in any of the vaccines used in New Zealand2. Bringing up this issue in the context of New Zealand vaccines (implied as this is a New Zealand organisation geared towards New Zealand residents) is at best ignorant and at worse disingenuous scaremongering. Even so it is useful to deconstruct the post anyway as it is indicative of the faulty reasoning and scientifically inaccurate content of the IAS website.

The post includes a link to the Material Safety Data Sheet (MSDS) for Ethyl Mercury as support for this claim3. The relevant part of the MSDS has been reproduced below to give an indication of what the post considers concerning about the use of Thimerosal in vaccines.

Quoting from the MSDS:

“Effects of Overexposure: Topical allergic dermatitis has been reported. Thimerosal contains mercury. Mercury poisoning may occur and topical hypersensitivity reactions may be seen. Early signs of mercury poisoning in adults are nervous system effects, including narrowing of the visual field and numbness in the extremities. Exposure to mercury in utero and in children may cause mild to severe mental retardation and mild to severe motor coordination impairment.”

This is used in conjunction with a video link on the page4 to advance the hypothesis that Thimerosal in vaccines causes  autism, despite the fact that the symptoms listed are explicitly due to overexposure, not the trace exposure that  constitutes the vaccine dose. This type of “any level is harmful” approach to medicine neglects the dose response  relationship of drugs and other chemicals in the body. This hypothesis also ignores scientific research into
mechanisms of autism, the epidemiology of the increase in autism reports and the failure of the hypothesis to account for the continued rise of autism cases after Thimerosal was removed from the majority of vaccines.

The web-based resource Science Based Medicine has a reference page containing summaries of and links to the various studies showing no link between Thimerosal in vaccines and development of autism or autism spectrum disorder (ASD)5. The studies in aggregate looked at the claim of a link between Thimerosal and autism in a number of ways. Several looked at large groups of individuals and attempted to find any sort of correlation between childhood exposure to Thimerosal and development of autism symptoms. All together these studies combed through the data of over 750,000 individuals in several different countries and found no evidence to support a link.

Continuing to disseminate information that implies a link between Thimerosal and autism is to be either wilfully ignorant of the current state of research, in which case claims to educational content are not accurate, or to be dismissive of the current research as being an inaccurate reflection of the facts. This second option depends on there being some sort of conspiracy within the scientific/medical community to hide the truth. No such conspiracy can be substantiated.
As an side, the MMR vaccine has also been linked to development of autism in the minds of anti-vaccine campaigners since Andrew Wakefield’s now discredited and retracted paper in the Lancet6. A Cochrane review of the evidence shows

“No credible evidence of an involvement of MMR with either autism or Crohn’s disease was found.”

and

“Exposure to MMR was unlikely to be associated with Crohn’s disease, ulcerative colitis, autism or aseptic meningitis…”7

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Footnotes:
1. Thimerosal clarification of chemistry:
The chemical IUPAC name of Thimerosal is actually
Ethyl(2-mercaptobenzoato-(2-)-O,S)mercurate(1-) sodium.
This breaks down to Ethyl Mercury in the body.
http://en.wikipedia.org/wiki/Thiomersal

2. Vaccine ingredients:
a. Childhood vaccine Schedule:
http://www.moh.govt.nz/moh.nsf/indexmh/immunisation-schedule-html
http://www.betterhealth.vic.gov.au/bhcv2/bhcmed.nsf/pages/wycpreve/$File/wycpreve.pdf
http://www.betterhealth.vic.gov.au/bhcv2/bhcmed.nsf/pages/gwcinfih/$File/gwcinfih.pdf
http://www.betterhealth.vic.gov.au/bhcv2/bhcmed.nsf/pages/gwcinfiv/$File/gwcinfiv.pdf
http://www.betterhealth.vic.gov.au/bhcv2/bhcmed.nsf/pages/gwchibrx/File/gwchibrx.pdf
http://www.betterhealth.vic.gov.au/bhcv2/bhcmed.nsf/pages/gwcbostv/$File/gwcbostv.pdf
http://www.betterhealth.vic.gov.au/bhcv2/bhcmed.nsf/pages/cscgarda/$File/cscgarda.pdf

b. Influenza Vaccines:
http://www.moh.govt.nz/moh.nsf/indexmh/influenza-a-h1n1-2010-faqsseasonal#safety
http://www.moh.govt.nz/moh.nsf/Files/swineflu/$file/vaxigrip.pdf
http://www.moh.govt.nz/moh.nsf/Files/swineflu/$file/Fluvax.pdf
http://www.moh.govt.nz/moh.nsf/Files/swineflu/$file/Influvac.pdf

3. MSDS cited on the IAS website:
http://www.vaccine-tlc.org/docs/Thimerosal%20Material%20Safety%20Data%20Sheet.pdf

4. Misleading video posted under the heading “Thimerosal in your Vaccine?”:
http://www.youtube.com/watch?v=m-Frdv9iR3E

5. The Science-Based Medicine resource page on Vaccines and Autism:
http://www.sciencebasedmedicine.org/reference/?p=1

6. Andrew Wakefield:
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2810%2960175-4/fulltext
http://www.bmj.com/content/342/bmj.c7452.fullhttp://www.nature.com/ajg/journal/v105/n5/full/ajg2010149a.html

7. Cochrane review:
http://www2.cochrane.org/reviews/en/ab004407.html