Mercury autism

Thimerosal is a preservative used in vaccines that has been purported to cause autism in children. The assumption is that thimerosal, also known as ethyl mercury, causes similar effects as methyl mercury, which has neurotoxic and nephrotoxic... 

A 2004 report by the Institute of Medicine s Immunization Safety Review Committee concluded that available evidence favored rejection of a causal relation between thimerosal-containing vaccines and autism. In like manner, a recent retrospective cohort study conducted by the CDC did not support a causal association between early prenatal or postnatal exposure to mercury from thimerosal-containing vaccines and neuropsychological functioning later in childhood. 

In the 15 years since these criteria were promulgated by declaration, it will be evident that most vaccines are still administered parenterally with the exception of polio and typhoid vaccines. In many ways this can be attributed to the physicochemical characteristics of vaccine antigens themselves, which are large molecules susceptible to proteolytic degradation, denaturation, and rapid clearance from plasma. Some combination vaccines are available which reduce the number of injections. However, the MMR (measles, mumps, and rubella) combination vaccine has gained an unsafe image in the popular press, mainly due to a reputed link with autism in some children that as yet remains unproven scientifically. In some quarters the autism was associated with the use of thiomersalate as a mercurial preservative in multidose injections but, again, this supposition remains unproven. 

Combination vaccines are more convenient in use and are exploited in the familiar DPT and MMR vaccines. However, there is always the possibility of autoimmune reactions and an increased risk of side effects. As noted, these issues have been obscured legally by claims that autism in children is caused by such combinations or the use of thiomersalate as a mercurial preservative. Scientifically it is probably safe to say that these side effects have not been demonstrated convincingly but these issues have caused difficulties for the manufacturers. 

Bernard S, Enayati A, Roger H, Binstock T, Redwood L. The role of mercury in the pathogenesis of autism. Mol Psychiatry 2002 7(Suppl 2) S42-3. 

Palmer RF, Blanchard S, Stein Z, et al. Environmental mercury release, special education rates and autism disorder An ecological study in Texas. Health Place 2006 12(2) 203 9. 

Schechter R, Grether JK. (2008) Continuing increases in autism reported to California s developmental services system mercury in retrograde. Arch Gen Psychiatry 65 19-24. 

Reanalysis of some older data has revealed that a significant relation does exist between blood levels of mercury and a diagnosis of autism. Hair sample analysis of mercury suggests that people with autism may be less efficient and more variable in eliminating mercury from blood.72... 

The vaccine-mercury linkage, recently under heavy suspicion as a cause of postnatal autism, is no longer considered significant. The reason given is that the cessation of the use of postnatal vaccines containing mercury (in the compound thimerosal) as a preservative has produced no decrease in the prevalence of autism.73 But there might be other reasons for the absence of a decrease in prevalence other than an absence of linkage. 

Desoto, M. C. Hitlan, R. T. (2007). Blood levels of mercury are related to diagnosis of autism a reanalysis of an important data set. J. Child Neurol. 22 1308—1311. 

Schultz ST. Does thimerosal or other mercury exposure increase the risk for autism A review of current literature. Acta Neu-robiol Exp (Wars) 2010 70(2) 187-95. 

The debate about the relation between autism and mercury (as thimerosal) in vaccines continues, without useful conclusions [37 ]. In a population-based study of the pharmacokinetics of mercury after immunization of 72 premature infants weighing 2000-3000 g at birth, the mean maximal blood mercury concentration was 3.6 fig/l, and it occurred at 1 day after immunization the maximal mean stool mercury concentration was 35 ng/g, and it occurred on day 5 urine mercury was almost undetectable [38 ]. The blood mercury half-life was 6.3 (95% Cl = 3.9S.8) days, and mercury concentrations returned to prevaccination values by day 30. The blood half-life of intramuscular ethyl mercury from thimerosal in vaccines given to premature infants is substantially shorter than that of oral methyl mercury in adults. Because of the differing pharmacokinetics, exposure guidelines based on oral methyl mercury in adults may not be accurate for children who receive thimerosal-containing vaccines. 

I. Hertz-Picciotto, P.G. Green, L. Delwiche, Blood mercury concentrations in CHARGE study children with and without autism. Environ. Health Perspect. 118 (1) (2010) 161-166. 

Mercury inhalation has been linked to Alzheimer disease and autism, and limitation to mercury emissions is currently the subject of legislation by the U.S. Environmental Protection Agency (ERA) who will impose limits on mercury emissions from coal-tired boilers in the utilities industry. Mercury control techniques currently used in the industry include the use of flue-gas desulfurization (EGD) units and, as a result of mercury measurements around these units, it is known that oxidized and not elemental mercury is removed by the EGDs. Consequently, one method to increase mercury removal by this type of unit is to introduce a catalyst to promote the oxidation of mercury. Mercury measurement [128,129] led to the discovery that a gold-coated sand sample in a simulated flue-gas environment absorbed elemental mercury until an equilibrium was established and desorption of oxidized mercury began. Individual components of the simulated flue-gas have been evaluated for their effect on the oxidation of mercury, and it was found that nitrogen dioxide and hydrogen... 

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