The first bill filed for next year’s state senate session would ban thimerosal in vaccines. Thimerosal is a preservative formerly used in many vaccines, now mostly found only in flu vaccines. Because it contains a form of mercury, people have tried to link its use in childhood vaccines with rising autism rates. As the Lawrence Journal-World’s Scott Rothschild notes:

Federal officials maintain there is no association between the disorders and thimerosal. Critics, however, say the studies are flawed and note that mercury is a known toxin.

Unfortunately, he leaves out a lot of background. The form of mercury used in thimerosal is not the one that people think of when we think of toxic mercury. The flaws claimed to exist in studies that find no link between thimerosal and autism are as nothing compared with gaping void of epidemiological evidence for such a link.

The simplest point to be made is that rates of autism rose at the same pace in areas that phased out thimerosal earlier and later, and show no change during the phase-out. The rise in autism diagnoses can be attributed to better knowledge of autism and better diagnostic tests, not necessarily to any novel causative agent, and certainly not thimerosal.

Furthermore, as I said, thimerosal is not used in childhood vaccinations any more. This bill is a waste of time. Its only effect would be to complicate the sale of flu vaccines in Kansas. Alas, the bill seems to have bipartisan support.


  1. #1 Trey Jackson
    December 11, 2006

    There have been good studies that have ruled out the possibility that higher rates of autism being due to better diagnostic tests.

    But your point about Thimerosol is true.

  2. #2 Josh
    December 11, 2006

    Really? I wasn’t aware of those studies. Tell me more.

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