Mercury in Vaccines: History & Toxicity.

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Mercury in Vaccines: History & Toxicity.

Wasn’t mercury removed from vaccines? Is mercury in vaccines safe? These are questions that parents typically have when they begin to research vaccines.
“In some states, if a doctor takes that multi dose vial [flu vaccine] and drops it by mistake on the floor, and it breaks, he is required by law to evacuate the building and to bring in hazmat crews to clean it up before the building can be reoccupied.”
– RFK Jr, The Truth About Vaccines (Epidode 4)


Mercury has been added to vaccines to preserve and prevent bacterial contamination of multi-dose shots (1,2). It is in vaccines in the form of a compound called thimerosal, and once injected into the body via intramuscular injection, it is rapidly broken down into thiosalicylate and ethylmercury (1). Ethylmercury is an organic toxic mercury compound and the focus of the debate over mercury in vaccines.
To re-state: Mercury in vaccines is in the form of a compound called thimerosal, which breaks down into ethylmercury.
In 1999, the American Academy of Pediatrics and the Public Health Service called for mercury to be taken out of vaccines because they discovered that the amount of mercury in certain vaccines which were given to infants far exceeded the EPA reference dose or exposure threshold for how much mercury that any individual should be exposed to in one day.
EPA Reference Dose = 0.1 mcg/kg/day (2,3,4).
Please note that the EPA reference dose is based on the compound methylmercury, not ethylmercury. The safety level of ethylmercury has never been scientifically determined, so federal agencies and the World Health Organization use methylmercury instead.
Though the thimerosal content of most vaccines was reduced to “trace amounts” (0.3-1.0mcg mercury per dose) or eliminated after 1999, unfortunately, the total amount of mercury a child from 6 months to 18 years of age will receive through the recommended CDC vaccination schedule, has actually increased since the AAP called for its removal (6). The reason for this was that in 2002, the CDC began recommending that pregnant women and infants as young as 6 months get annual flu shots at 1-2 doses each season.


Question: Is the amount of mercury in flu and meningococcal vaccines toxic?
Vaccines which contain mercury are multi-dose influenza vaccines (though independent tests have suggested other vaccines may be contaminated).
Thimerosal-preserved “multi-dose” flu shots contain 25mcg mercury per dose. Surprisingly, even some vaccines labeled “preservative free” (“thimerosal free” or “no mercury”) – actually still contain trace amounts of mercury (2). Children from 6 months to 35 months of age receive a half-dose of the flu shot. Children three years of age or older, and adults, receive a full dose ( 21-36 million multi-dose flu shots have been produced for the US in the 2017-2018 season. 
In one multi-dose flu shot, a six-month-old receives 12.5mcg mercury (a half dose) which is over 16x the safe dose per the EPA (calculations below). A three-year-old receives 25mcg mercury via the flu shot, which is almost 18x the safe dose per the EPA. In one mutli-dose meningococcal vaccine, an 11-12 year-old receives over 6x the safe dose of mercury per the EPA. At 25mcg mercury per dose, an individual would have to weigh over 550lbs to approach the safe exposure level.
Therefore, the multi-dose flu shot is toxic to every person who receives it.
Average 6-month-old infant weight = 16.5lbs or 7.5kg
EPA reference dose or allowable limit for average 6-month-old:
7.5kg (0.1mcg/kg/day) = 0.75mcg/day
1/2 dose flu shot for children ages 6-35 months contains 12.5mcg mercury.
(12.5mcg) / (0.75mcg) = 16.67
The amount of mercury in your infant’s flu shot is over 16x the “safe” limit.

Methyl vs. Ethyl.
There are several different forms of mercury that we might encounter, and the type and route of exposure dictates its toxicity. The different routes of exposure are dermal, inhalation, ingestion, and injection. For example, the mercury in a thermometer is elemental mercury and won’t readily absorb through the skin. But if you were to burn that amount of mercury and inhale the vapors, it would be toxic to internal organs. That same amount of mercury in an organic form would quickly absorb through the skin, into your body, and reach your bloodstream. Organic mercury can pass through the placenta, exposing a developing fetus. Therefore, the form of mercury and route of exposure is important (7,8).
Methylmercury and ethylmercury are organic mercury compounds. Methylmercury has been extensively studied as a result of its accumulation in fish. The FDA even advises against eating too much of certain species in order to reduce our exposure. But when it comes to ethylmercury, the CDC claims that the amount of ethylmercury in vaccines is safe. The CDC website covers the topic of thimerosal (and ethylmercury) in vaccines, yet lists only one scientific study from the past decade. It’s stated that ethylmercury in vaccines is “cleared from the body more quickly than methylmercury, and is therefore less likely to cause any harm” (1). When the CDC makes this statement, what they’re referring to is that the amount of ethylmercury in the blood – after it’s injected through a vaccine – drops more quickly than methylmercury would (9). The problem with this statement is that they’re allowing readers to make the assumption that blood levels of ethylmercury drop because it’s being eliminated from the body, and no longer poses the threat of toxicity. Unfortunately, this is a half-truth. Blood levels drop because much of it is quickly going to the brain and other organs, where it gets converted to inorganic mercury, gets trapped, and becomes difficult to remove. It’s also been found that ethylmercury ends up depositing twice as much inorganic mercury into the brain than would an equal amount of methylmercury from consuming contaminated fish (10). Therefore, the CDC’s statement that ethylmercury is safer than methylmercury is misleading at best. A reference dose for ethylmercury based on injection, not ingestion, should be determined based on finding the NOEL (No Observed Effect Level), considering the fact that vaccination targets our most sensitive populations – infants, children, and the developing fetus (11).
Evidence of toxicity.
Contrary to what the CDC has to say about the safety of mercury or thimerosal in vaccines, over 165 scientific studies have been published on thimerosal and found it to be harmful (12). These studies have found that exposure to thimerosal has been associated with: neurotoxicity (13,14) and excitotoxic brain injury (15,16), lasting neuropathological changes (17), neurodevelopmental disorders and autism (14,16,18,19), immune system stimulation and inducing autoimmunity (20,21), kidney toxicity (22), modification of hormone levels (16), mitochondria toxicity (23), fetal toxicity (24,25,26), DNA damage (27), and more. When it comes to child development, thimerosal exposure has also been found to be a risk factor for tics, speech delay, language delay, neurodevelopmental delay, delayed startle response, decreased motor learning, and attention deficit disorder (12,25,26,28).


1. CDC > Vaccine Safety > Thimerosal in Vaccines
2. FDA > Vaccines, Blood, & Biologics > Thimerosal in Vaccines
3. CDC > Morbidity and Mortality Weekly Report > Notice to Readers: Thimerosal in Vaccines: A Joint Statement of the American Academy of Pediatrics and the Public Health Service.
4. EPA > National Center for Environmental Assessment > Risk Assessment > Reference Dose for Methylmercury
5. Medscape > Influenza virus vaccine trivalent (Rx) > Dosing & Uses > Pediatric
6. “Ten Lies” told about Mercury in Vaccines
7. CDC > Environmental Health Document > Mercury > 2009
8. Agency for Toxic Substances & Disease Registry (ATSDR) > Toxic Substances Portal – Mercury > Public Health Statement on Mercury, March 1999.
9. Neurotoxic character of thimerosal and the allometric extrapolation of adult clearance half-time to infants.
10. Comparison of blood and brain mercury levels in infant monkeys exposed to methylmercury or vaccines containing thimerosal.
11. EXTOXNET > Toxicology Information Brief > Dose-Response Relationships in Toxicology
12. Methodological issues and evidence of malfeasance in research purporting to show thimerosal in vaccines is safe.
13. Integrating experimental (in vitro and in vivo) neurotoxicity studies of low-dose thimerosal relevant to vaccines.
14. Transcriptomic analyses of neurotoxic effects in mouse brain after intermittent neonatal administration of thimerosal.
15. Administration of thimerosal to infant rats increases overflow of glutamate and aspartate in the prefrontal cortex: protective role of dehydroepiandrosterone sulfate.
16. A possible central mechanism in autism spectrum disorders, part 2: immunoexcitotoxicity.
17. Lasting neuropathological changes in rat brain after intermittent neonatal administration of thimerosal.
18. A dose-response relationship between organic mercury exposure from thimerosal-containing vaccines and neurodevelopmental disorders.
19. The biological basis of autism spectrum disorders: Understanding causation and treatment by clinical geneticists.
20. Immunosuppressive and autoimmune effects of thimerosal in mice.
21. Ethylmercury and Hg2+ induce the formation of neutrophil extracellular traps (NETs) by human neutrophil granulocytes.
22. A systematic study of the disposition and metabolism of mercury species in mice after exposure to low levels of thimerosal (ethylmercury).
23. Thimerosal-Derived Ethylmercury Is a Mitochondrial Toxin in Human Astrocytes: Possible Role of Fenton Chemistry in the Oxidation and Breakage of mtDNA
24. The effect of ethylmercury on fetal development and some essential metals levels in fetuses and pregnant female rats.
25. Low-dose mercury exposure in early life: relevance of thimerosal to fetuses, newborns and infants.
26. Maternal thimerosal exposure results in aberrant cerebellar oxidative stress, thyroid hormone metabolism, and motor behavior in rat pups; sex- and strain-dependent effects.
27. Thimerosal Induces DNA Breaks, Caspase-3 Activation, Membrane Damage, and Cell Death in Cultured Human Neurons and Fibroblasts.
28. Exposure to Mercury and Aluminum in Early Life: Developmental Vulnerability as a Modifying Factor in Neurologic and Immunologic Effects.