Thimerosal and Neurotoxicity
The effect of mercury exposure in children once again proves difficult to determine.
Considerable controversy surrounds the question of whether mercury preservatives in vaccines, such as thimerosal, are associated with impaired behaviors or cognition in children (see Journal Watch Psychiatry Aug 4 2004). These researchers examined 42 measures of neuropsychological and behavioral functioning in children aged 7 to 10 years from four HMOs. Using histories of vaccination, immunoglobulin experience, and other records, the researchers retrospectively calculated mercury exposure at three time points: neonatal (i.e., maternal), the first 28 days of life, and the first 7 months.
Children with low birth weight, meningitis, encephalitis, or other serious neurological diagnoses were excluded. The 1047 tested children represented only 30% of those eligible. Children of parents with the highest socioeconomic indicators had the highest exposure. Small yet significant negative and positive associations, some sex-specific, were identified between some individual neuropsychological tests and thimerosal exposure.
Comment: The authors, who expertly analyzed these data statistically, conclude that thimerosal does not produce meaningful clinical problems. However, the validity of this conclusion needs to be questioned because of possible confounding in the study sample. First, only 30% of cases were studied; how these cases may have differed from those who did not participate was not discussed. Second, the data were collected retrospectively. Third, the cases that were excluded — e.g., low-birth-weight babies — might be the ones most vulnerable to the effect of a neuroactive substance, but this issue was not addressed. Finally, the threshold dose for neurological impairment is unknown; therefore, to dismiss the vaccines given between ages 12 months and 7 years may be premature. Parents who ask about this issue still need to be informed of the complexities of studying this problem.
— Barbara Geller, MD
Published in Journal Watch Psychiatry September 26, 2007
Citation(s):
Thompson WW et al. Early thimerosal exposure and neuropsychological outcomes at 7 to 10 years. N Engl J Med 2007 Sep 27; 357:1281.
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About Me
- BB
- I am a British Psychologist specialising in Autism and related disorders with longstanding and growing concerns about: How much certain vaccines have affected certain children. How much Thimerosal, a preservative which is 49.6% Mercury, has damaged certain children over 77 years. How much MMR has damaged certain children and the synergistic effect of the effect on the immune system of: DTP (with Thimerosal) and MMR on certain children. How spin and political pressure has been used to dismiss real scientific evidence of biological damage. How spin has been used to blame parents for deaths and damage to children following certain vaccines. How spin has been used to vilify professionals including myself for raising these deeply moral issues affecting our most vulnerable citizens. Some years ago I wrote a book - Reweaving the Autistic Tapestry, now available on Amazon but not without a struggle. See the stories unfold over the next days and weeks about how the Pharmaceutical Industry with Government agencies have done so much to hide the truth about the damage they have done.