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Over 60 years ago the FDA approved a little known product, thimerosal, to be used as a preservative. Today many people question whether this product is responsible for the current epidemic of children diagnosed with learning disabilities and autism.

Current thinking suggests that exposure to mercury comes primarily from environmental and dietary sources, dental amalgams and rare catastrophic events. Recently, however, another common and pervasive source of mercury exposure has been identified–thimerosal. Thimerosal was first approved as an additive by FDA in the 1930s. It has been utilized as a preservative to prevent bacterial contamination in a number of blood and biological products, including vaccines, immune globulins, and over-the-counter eye and nose drops. The danger that thimerosal presents is that it contains 49.5% ethyl mercury by weight. Mercury is a potent human toxin that has long been the source of many serious health problems. Mercury is especially toxic to the rapidly developing fetal and infant brain. While acceptable levels for exposure are published by Federal Agencies, mercury is a poison at any level.

Chemically, thimerosal is a water soluble, cream colored crystalline powder. In the human body thimerosal is metabolized to ethylmercury and thiosalicylate. The literature on thimerosal metabolism and excretion is old, and toxicological information is limited. Therefore, it has been assumed that the toxicity of ethylmercury is equivalent to that of methylmercury until further information is available. In the past there have been case reports of toxicity and death following inadvertent massive exposures.

FDA’s Discovery

The 1997 FDA Modernization Act required the FDA to compile a list of drugs and foods that contain intentionally introduced mercury compounds, and to provide a quantitative and qualitative analysis of the mercury compounds on the list. Although FDA’s mission is to ensure purity, safety, potency and efficacy of individual products, such analysis had never been a required part of the permitting process. In its review, which took two years to complete, the FDA discovered that infants who receive thimerosal-containing vaccines at several visits may be exposed to mercury in amounts higher than recommended by Federal guidelines for total lifetime mercury exposure.

Infant vaccines that routinely contained thimerosal were DPT, Hep.B and HiB. Following the CDC recommended vaccine schedule, infants were exposed to up to 187.5 mcg of ethyl mercury, depending on the vaccine manufacturer. Total exposure through 18 months could be as high as 237.5 mcg. (Table 1.) The dose thought to be allowable by EPA is 0.1 mcg per kilogram per day. If an average 5 kg infant received all thimerosal-containing vaccines at his 2 month visit, the exposure that day would be 62.5 mcg ethyl mercury, an exposure that is 125 times above the EPA’s guideline.

In its analysis, the FDA multiplied EPA’s daily exposure levels of 0.1 mcg per kilogram by 180 days, even though the exposures had occurred on only 4 days during this time period. It is perplexing that the FDA chose to average an infant’s total exposure to mercury over the first six months of life, as though children were being exposed on a daily basis, and reported that amounts were only slightly above one of the Federal guidelines. According to toxicologists, because of the inherent pharmokinetics of mercury and its long half-life in the body, it is not possible to legitimately calculate the effect of a large injected bolus dose as though it were a small amount administered over a longer period of time. This method of analysis fraudulently minimizes the levels of exposure. If one were to look at the mercury in thimerosal from a daily dose perspective, not one vaccine containing thimerosal would be able to meet EPA’s guidelines for safe exposure. That’s like claiming that taking 4 Tylenol a day at 6-hour intervals for a month is an “equivalent dose” to taking 120 Tylenol in one day.

At the same time the FDA findings were released, The American Academy of Pediatrics published An Interim Report to Physicians on Thimerosal in Vaccines. In this document, the AAP and Public Health Service agreed that the use of thimerosal-containing vaccines should be reduced or eliminated, stating that any potential risk was of concern. While the document discussed much of the uncertainty regarding the potential effect of mercury exposure in vaccines, it clearly stated that there was no evidence of harm having occurred from this exposure. The Academy also recommended, “Infants and children who have received thimerosal-containing vaccines do not need to have blood, urine, or hair tested for mercury, since the concentrations would be quite low and would not require treatment.” If no testing for mercury was recommended, then how could one know, for a fact, that there is “no evidence of harm”?(1)

Historical Perspective

It is interesting to note that thimerosal was introduced only a few short years before Dr. Leo Kanner described a new mental disorder which differed “markedly and uniquely from anything reported” before. In its early history autism was diagnosed more frequently in affluent families, but became more evenly distributed socioeconomically by the 1970s. This apparent widening in demographics paralleled the increasing availability of vaccines to all children through federally sponsored programs. It has been during this same time period–the 1980s, and especially the 1990s–that we have witnessed a tremendous increase in the occurrence of the spectrum of autism disorders. (Table 2.)

In the late 1980s and early 1990s the vaccine schedule was amended to include both Hepatitis B and HiB vaccines. Each vaccine is administered to infants 3 times during the first six-months of life. Their addition to the vaccine schedule potentially tripled an infant’s exposure to mercury if they received all thimerosal-containing vaccines. An additional concern is that these vaccine exposures are occurring on top of prenatal exposures from thimerosal-containing immune globulin preparations administered to RH- mothers during pregnancy, and in addition to dietary, dental and environmental exposures.

Current Investigations

Recent information from large epidemiological studies conducted in mercury-exposed populations suggests that intermittent large exposures may pose a higher risk than small daily exposures. In one study, lower scores on memory, attention, language and motor function tests were found years later in children who had been exposed prenatally to intermittent bolus doses of methyl mercury from dietary exposure at levels that had been previously thought to be safe.(2)

In a recent investigation, mercury levels were obtained before and after exposure to 12.5 mcg of ethyl mercury in hepatitis B vaccine in 15 preterm and 5 term infants.(3) There were no differences between the preterm and term infants with respect to mean pre-vaccination levels, although post immunization mercury levels were significantly increased in both groups of infants. Post vaccination levels in preterm infants were 3 times higher than those of term infants, a difference that was statistically significant. Of interest, one preterm infant developed a post vaccinal mercury level of 23.6 mcg/L, which falls within the range known to result in neurodevelopmental dysfunction.(4)

At the June 21, 2000 Advisory Committee for Immunization Practices meeting held in Atlanta, Georgia, Dr. Thomas Verstraeten of the National Immunization Program presented a review of vaccine safety datalink information on thimerosal-containing vaccines. Over 400,000 children participate in the vaccine safety datalink program. From this database, 100,000 eligible children’s charts were reviewed to determine exposure to thimerosal-containing vaccines and specific neurodevelopmental outcomes. Key findings were statistically significant associations between cumulative exposure to thimerosal-containing vaccines.

A recent report in the Weekly Epidemiology Record, January 2000, reviewed the use of thimerosal as a vaccine preservative. The report stated that “this safety assessment cannot currently exclude the possibility of subtle neurodevelopmental abnormalities in infants from a cumulative exposure to thimerosal in vaccines.”(5)

What Next?

There are many unknowns with respect to thimerosal. These include: a paucity of data on the metabolism, excretion and toxicity of ethyl mercury, the levels of risk to the fetus from maternal exposures and to the infant from exposure occurring during critical windows of neurological development, and the effect of large intermittent bolus exposures to ethyl mercury verses daily low dose oral exposures to methyl mercury. Current investigations are underway from both governmental and private agencies in an effort to address these concerns.

Many questions concerning mercury exposure from thimerosal in vaccines remain unanswered, and there is little consensus as to how best to proceed to diagnose, or effectively treat elevated mercury levels in children. The effectiveness of chelating agents in crossing the blood brain barrier has become a topic of scrutiny, as well as the ability to treat a long-standing exposure which occurred during a critical time in development.

At a recent Defeat Autism Now (DAN) Conference a number of physicians who specialize in the treatment of children with autism and developmental disorders reported many children with elevated mercury levels had remarkable improvement in behavior, speech and cognition when treated with a program to reduce oxidative stress and metal body burden.

What to do

Despite this information, the FDA has only “encouraged” vaccine manufacturers to reduce or eliminate thimerosal. Dr. Neal Halsey at the Institute for Vaccine Safety, Johns Hopkins, summed up this issue best in a recent article on thimerosal published in the Hepatitis Control Report, Summer 1999 issue. “We can say there is no evidence of harm (from thimerosal), but the truth is no one has looked.”(6) Until more research is available, it would be prudent to use thimerosal-free vaccines. [Or avoid vaccines altogether–WD]

Currently, there are still 30 thimerosal-containing vaccine products on the market. The general public, as well as physicians and health professionals, need to be aware that thimerosal-free vaccines exist. Parents research the safest car seats and toys for their children, but do not realize that they also need to research vaccines as well. Thimerosal has been eliminated from latex paints, merthiolate and many other over-the-counter products because of serious toxic effects in infants from these products. Although FDA has only focused on thimerosal in infant vaccines at this time, all vaccines that contain this product should be scrutinized.

Additional Information

For additional information on mercury and autism: www.safeminds.org or http://tlredwood.home.mindspring.com

To a review paper on Autism and Mercury: www.canfoundation.org/newcansite/sciwatch/invest.html

For vaccine products and thimerosal content: www.immunize.org/news.d/thimtabl.htm

For additional information on vaccines go to www.909shot.com


1. American Academy of Pediatrics. Thimerosal in vaccines-An interim report to clinicians. Available at http://www.aap.org/new/thimpublic.html.

2. Grandjean P, Weihe P, White, RF, Debes F. Cognitive performance of children prenatally exposed to “safe” levels of methylmercury. Environ Res. 1998; 77: 165-172.

3. Stajich, G, Loez, G, Harry W, Sexson W. Iatrogenic exposure to mercury after hepatitis B vaccination in preterm infants. J. of Peds. 2000; 136 (5); 679-681.

4. Grandjean P. Weihe P, Nielse, J. Methylmercury: Significance of interuterine and postnatal exposures. Clin. Chem. 1994: 40 (7) 1395-1400.

5. Thimerosal as a vaccine preservative. Wkly Epi Rec. 2000; Jan 14; 75 (2): 12-16.

6. Uproar over a little-known preservative, thimerosal, jostles U.S. hepatitis B vaccination policy. Hep. Control Rep. Summer, 1999. Vol. 4, No.2.

Shared Symptoms of Mercury Exposure and Autism

Mercury toxicity is cumulative, resulting in delayed neurotoxicity which can manifest months after exposure. Many children with autism experience normal development and then regress.

Susceptibility to mercury also appears to have a genetic component–boys are more affected than girls by a ratio of approximately 4 to 1. Autism and ADD/ ADHD also occurs more frequently in boys than girls.

Although the major toxicity of mercury compounds is expressed in the central nervous system, the immune and gastrointestinal systems are also commonly affected. The same abnormalities in these systems have been found in children with autism.

Other shared symptoms of mercury exposure and autism include:

√ Speech and hearing deficits, including difficulty speaking and understanding speech.

√ Sensory disturbances, including numbness in the mouth, hands and feet, sensitivity to loud noises, aversion to touch and over or under response to pain.

√ Cognitive impairment and difficulty dealing with abstract ideas and complex commands, social withdrawal, anxiety and obsessive-compulsive behaviors.

√ Disruption of serotonin, dopamine, glutamate and acetylcholine neurotransmitters.

√ Damage to Purkinje cells and granule layer of the cerebellum in the brain, as well as the amygdala and hippocampus, while other areas are spared.

√ Pervasive and widespread dysfunction of enzymes, transport mechanisms and structural proteins.

√ Damage to the immune system triggering autoimmune processes, including shifts in the Th2 lymphocytes.

√ Increased susceptibility to certain virus strains, which may be related to a decrease in NK cell function.

√ Gastrointestinal disturbances and inhibit digestive enzymes and peptides. Many children with autism develop gastrointestinal problems and have difficulty digesting dairy and wheat products.

Nutritional Support for Mercury Detoxification

DMSA (2,3-Dimercaptosuccinic Acid) is a sulfhydryl-containing substance with a long history of use as an orally administered agent for toxic heavy metal poisoning. Extensive clinical research since the 1950s demonstrates that DMSA accelerates elimination of mercury from the brain and effectively removes mercury from the blood, liver and kidneys. DMSA has also been approved for use in the U.S. for the treatment of lead intoxication in children.(1,2,3,4)


While DMSA is the nutritional agent of choice for systemic mercury detoxification, EDTA (Ethylene-Dia-mine-Tetra-acetic Acid) is well-documented for its ability to safely remove many heavy metal toxins, including mercury.(5) EDTA, the active ingredient in VRP’s Oral ChelatoRx, is known to remove mercury from cell surfaces and the blood, but not from within cells, whereas DMSA is very effective in removing intracellular mercury and lead, especially from the brain. Evidence suggests that EDTA is less effective at removing mercury when used alone, but use in combination with DMSA may speed up the process of removal.


Since use of DMSA and EDTA may result in the depletion of certain elements, it is highly recommended that when using either or both of these formulas one also supplement with a potent vitamin and mineral formula, such as VRP’s Advanced Essential Minerals or Essential Minerals. Minerals should be taken with meals and not with the chelating agents formula(s).


1. Klaassen CD. Heavy Metals and Heavy-Metal Antagonists; Chapter 69; pp. 1615-1637; in Goodman and Gilman’s The Pharmacological Basis of Therapeutics (6th Ed.); 1980.

2. Aposhian HV. DMSA and DMPS – Water Soluble Antidotes for Heavy Metal Poisoning. Ann. Rev. Pharmacol. Toxicol.; 23: 193-215; 1983.

3. Pangborn JB. Mechanisms of Detoxification and Procedures for Detoxification. Doctor’s Data, Inc., and Bionostics, Inc., Chicago, IL., (708) 231-3649.

4. Ziff MF, Ziff S and Hanson M. Dental Mercury Detox. BioProbe, Inc., 1997.)

5. Gordon, GF. EDTA safe in treating patients with mercury toxicity. Townsend Letter, Feb/Mar 1997.

First Mercury Poisoning Vaccine Lawsuit Filed in US

A Texas law firm has filed the first known civil case involving the use of thimerosal-containing vaccines. The case, Counter, et al v. Abbott Laboratories, et al, (Cause No. GN 100866, 200th District Court – Travis County, Texas) was filed by Waters & Kraus, LLP, a Dallas, Texas-based law firm. The suit alleges that the mercury-based preservative thimerosal, used recently in more than 30 childhood vaccines, has caused mercury poisoning in many children

The symptoms of mercury poisoning are, in many cases, identical to the symptoms of autism, although the suit does not allege that all persons suffering from the symptoms of autism do so as a result of mercury poisoning. However, many children suffering from mercury poisoning have been previously diagnosed with autism due to the similarity of symptoms.

Children have been exposed to cumulative levels of mercury from the vaccines that exceed threshold safety levels that have been established by the United States Environmental Protection Agency.

In many instances, children carry unmistakable evidence of mercury poisoning and the symptoms of mercury poisoning were first manifested after receiving vaccines tainted by thimerosal. In many cases, children exhibited normal neurological and other developmental patterns until such time as the cumulative dose of mercury caused irreparable damage to both the neurological and the general developmental process.

Waters & Kraus anticipates that a significant number of individual cases against the vaccine industry will be filed in the near future.

The information in this article is not intended to provide personal medical advice, which should be obtained from a medical professional, and has not been approved by the U.S. FDA.

Copyright 2001 by Vitamin Research Products, Inc. (VRP) The use of information found in Vitamin Research News for commercial purposes is prohibited without written permission from VRP.
by Lyn Redwood, RN, MSN, CRNP

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