The Amount of Mercury (and Thimerosal) in Vaccines

Mercury and thimerosal are still used in many common vaccines

Mercury and thimerosal are still used in many common vaccines

Amalgam fillings. Thermometers. Batteries. Light bulbs. They can all contain toxic levels of mercury and all are used and sold on a daily basis around the world. But perhaps the most dangerous is the one that the Center for Disease Control (CDC) recommends on a regular basis — and something that has been saving lives for decades: Vaccines.

As the mercury debate rages on in the dental industry, it’s important to remember that the medical industry — pharmaceutical in particular — is no stranger to the conversation. In fact, the danger of mercury levels in common vaccines have been debated for decades. The primary target? Thimerosal.

In the 1930s, pharmaceutical companies introduced thimerosal — which contains mercury as a primary ingredient — as a preservative for vaccines (preservatives are required by the FDA for use in multi-dose vaccines to prevent bacterial contamination of biological products). Thimerosal has been used in more than 30 U.S. licensed vaccines since the 1930s to help prevent microbial growth during storage and use. It is also used in the manufacturing process for some vaccines.

Thimerosal is about 50 percent ethylmercury, whereas methylmercury is the predominant form of organic mercury in the environment. Many childhood vaccines contain between 12.5 to 25 micrograms of mercury. Through the eighties, it was in flu vaccine and various diphtheria/tetanus/pertussis vaccines. In the late eighties and early nineties, as hepatitis B and Hib vaccines were added to the immunization schedule, there were now more vaccines in the childhood immunization schedule that contained thimerosal.

Dr. Jay Liebermann,
Pediatric Infectious Disease Specialist, University of California, Irvine

Organic mercury is a well-known neurotoxin that can accumulate in the body’s soft tissue, such as the brain, and has been linked to problems such as Alzheimer’s, dementia, autism, and much more. Children and fetuses are especially susceptible. By using a preservative that contains 50% mercury in vaccines, children immunized with a thimerosal-preserved vaccine are receiving a neurotoxin directly through the blood stream.

(Methylmercury is considered the most dangerous form of organic mercury. Thimerosal contains ethylmercury, another form of organic mercury. While ethylmercury is thought to be less toxic than methylmercury, studies have been inconclusive and, as such, regulations and warnings have been applied equally to both ethyl and methylmercury. More specifically, any and all organic forms of mercury have been deemed a neurotoxin dangerous to children and fetuses, ad well as many adults.)

As reported by the Department of Health and Human Services Centers for Disease Control and Prevention during their Advisory Committee on Immunization Practices February 21-22, 2007 in Atlanta, Georgia “A goal of the 1997 FDA Modernization Act was to compile a list of drugs and foods that contained intentionally introduced mercury compounds and provide a quantitative analysis. The FDA concluded that infants who received thimerosal-containing vaccines at several visits could exceed the total mercury exposure recommended by Environmental Protection Agency guidelines.”(, Page 22)

In 1999, as a precautionary measure to maintain the public’s trust in immunization, the AAP/FDA U.S. Public Health Service issued a joint statement urging manufacturers to remove thimerosal from vaccines as soon as possible.

“Thimerosal as a preservative was removed from most childhood vaccines by 2001 and the last lots of thimerosal preservative-containing vaccines expired in January 2003. It is still being discussed only because of ongoing litigation in both state courts and the Vaccine Injury Compensation Program. Thimerosal is still contained in some of the flu vaccines routinely given to children since 2004. There are also vaccines that contain trace, often unmeasurable, levels of thimerosal.” (, Page 23)

While thimersosal — and, hence, mercury — is indeed being phased out in most vaccines, plenty of vaccines still contain the preservative, particularly multi-dose vaccines (as preservatives for multi-does vaccines are still mandated by the FDA). So how do you know if a vaccine is mercury-free and safe for children? Unfortunately, most doctors and vaccination clinics don’t have that information readily available and unless you specifically ask for a certain vaccine, you most often will not be provided a choice. Thankfully, Johns Hopkins Bloomberg School of Public Health has made identification of mercury-containing vaccines an easier task.

On September 18, 2009, The Institute for Vaccine Safety at Johns Hopkins Bloomberg School of Public Health published an updated list of Thimerosal Content in Some US Licensed Vaccines that you can view online at (they also have a PDF version you can download and print available at the same link).

While the list is not all-inclusive, it does provide updated information on mercury levels in many of the most popular and common vaccines (including the thimerosal and mercury levels in the N1H1 vaccines). A quick glance at the chart will indeed reveal that most single-dose vaccines are thimerosal-free while many multi-dose vaccines still contain the mercury-enriched preservative.

The CDC, the AAP, the FDA, and many other government and health organizations have widely acknowledged that organic mercury is a neurotoxin that can be incredibly dangerous to the human body — especially to children and developing fetuses. Why then, are high doses of mercury still allowed in such products as vaccines and mercury amalgam dental fillings? While the most common arguments are centered around the relatively low levels of mercury in the products (which should be irrelevant because mercury, as a “heavy metal,” cannot be processed by the human body and, therefore, accumulates in the soft tissue over time. Chronic or occasional exposure to even trace amounts of organic mercury can accumulate to lethal levels over time), what is the motivation behind allowing ANY level of known neurotoxins to remain on the market for human consumption?

The answers to those questions lie mostly in the political and financial realm. Unfortunately, until we begin to value health over politics and vitality over money, the debate will continue to rage at the expense of our health and the health of the world’s youth.

Update: Despite the risks (and regulations) associated with thimerosal and mercury in vaccines, Washington State has issued a 6-month suspension on safety limits of the preservative used in the H1N1 (swine flu) vaccine. For more details, please read our article “Washington State Suspends Safe Levels of Mercury in H1N1 Vaccine.”

For more great information about the dangers (or safety) of vaccines containing thimerosal, check out this article by Despite it’s relative age (written in 2005) it’s loaded with great research and a ton of great information. A “must-read” article if you have questions regarding thimerosal and mercury in vaccines.

(The preceding article is meant to provide information about thimerosal in vaccines. This article is for informational purposes only and is not intended as medical advise or to replace the advice of a qualified physician. Please consult your physician with any concerns or questions you have in regards to thimerosal and mercury in vaccines and which vaccines might be right for you and your loved ones.)

United States Department of Health and Human Services, Food and Drug Administration, “Vaccines, Blood & Biologics: Thimerosal in Vaccines”;

Johns Hopkins Bloomberg School of Public Health, The Institute for Vaccine Safety, “Thimerosal Content in Some US Licensed Vaccines”;

Department of Health and Human Services Centers for Disease Control and Prevention, Advisory Committee on Immunization Practices, February 21-22, 2007 in Atlanta, Georgia; “THIMEROSAL: REVIEWING THE EVIDENCE” (Pages 21-26), Dr. Jay Liebermann, Pediatric Infectious Disease Specialist, University of California, Irvine;



  1. first of all fda and cdc both got caught lieing about mercury in vaccines . they now just take it off from the ingredient listing as for the commenter look it up takes 5 min .his comments show how a sleep he is to the truth and its not 200,000 to 500,000 got the flue and die try 35,000 .next time look up your facts be for you comment .

  2. I came across this website after listening to Dr. Marvin on the radio, and after reading much of the articles here, I agree with Jason that many of the articles here are alarmist in nature and meant to scare people into becoming patients. This almost reminds me of the anti-bacterial hype that internet and late night infomercial marketers were producing to scare people into buying their products. In this case, it’s the notion that millions of people have ticking mercurial time bombs in their mouth that need to be replaced at $300 a pop before they go crazy. Now, I 100% agree that mercury is not a good thing, as evidenced by my crazy grad school chemistry professors who I swore inhaled a bit too much mercury vapor in their day, but I also firmly believe that old “silver” fillings are better left alone unless they’re found to be failing, or you think they’re just plain ugly, which was my primary reason for going with composites.

    With regards to vaccines, go to any physician and they’ll tell you that thimerosal preserved vaccines make up only a small percentage of the available options out there. I like that Dr. Marvin referenced the link to the John’s Hopkins report – and anyone who took the time to peruse the report will find that for almost every thimerosal preserved vaccine, there are 3 or 4 non-thimerosol options that most physicians will recommend. Of course no obvious mention of this was made, and the blog entry continues to infer that vaccines are bad and you’re going to accumulate a mass amount of neurotoxin that will become lethal over time. Forget the fact that 200-500 thousand people die from the flu every year, yet mercury related deaths are so insignificant that you would be hard pressed to find official numbers on the subject. The most significant mercury poisoning episode in recent human history was the Minamata, Japan incident, which killed less than 2000 people…and that was more than 60 years ago. These poor souls were DIRECTLY exposed to high levels of mercury on a daily basis via wastewater from a nearby plant…nothing close to the amount of mercury sitting in your molars or in a vaccine.

    In Dr. Marvin’s defense, I applaud his marketing prowess in going after a market that most conventional dentists probably ignore, that is the i’ll-try-any-product-with-the-word-natural-in-it holistic population. Everyone needs to make a buck…nothing wrong with that at all.

    • David, thank you for the response. I always appreciate honest, well-thought-out and educated comments. In the article I suppose I didn’t do a good job of explaining that there are mercury-free alternatives to many thimersosal-containing vaccines (I tried to make that clear when I said “While thimersosal — and, hence, mercury — is indeed being phased out in most vaccines, plenty of vaccines still contain the preservative, particularly multi-dose vaccines (as preservatives for multi-does vaccines are still mandated by the FDA).” I should have been more clear and will edit that portion of my article to reflect that most single-dose vaccines are thimersosal free.

      In regards to your comment that I’m trying to “scare people into becoming patients,” it’s hard to substantiate when you look at our web statistics and see that more than 93% of our web visitors come from outside San Diego County. In fact, a large portion of our visitors come from overseas. Most of our business comes from referrals from patients who are very happy with the dental care we provide and have never seen our website (nor will they ever see it). And while we do perform safe mercury removals, we are selective in who we provide this service to and perform very few (nor do we care to — they are labor and time-intensive procedures with very little profit margin).

      Our main goal on the website is to inform the public. Most of our visitors come via web searches for specific information on the dangers of mercury. There are a disproportionate number of websites providing information that will extol the benefits of amalgam fillings and applaud the ADA for maintaining their position on amalgam and ignoring the scientific research at hand (in fact, contrary to popular belief, amalgam fillings have a higher profit potential for most dentists because they are a much easier filling material to work with and many insurance companies will pay for them).

      The notion that organic mercury is neurotoxin is indisputable. What most people don’t understand is that toxicity does not often occur via mass exposure (as happened in the Minamata incident you mentioned), but rather, via accumulation of the toxin in low doses over long periods of time. While no one will probably “explode” as a result of this “ticking time bomb,” being exposed to low doses (as are found in mercury amalgam fillings) can have an adverse affect on one’s health. It’s similar to asbestos (another toxin that was deemed safe by authorities before it was finally proven dangerous and rapidly removed from schools and everywhere else it had been used). Very few people have immediate health issues as a result of mass exposure to asbestos. Rather, the health affects are incurred over time as a result of consistent, low-level exposure.

      I appreciate your comment. I don’t have the false belief that everyone will agree with our positions — quite the contrary — and I appreciate the impassioned and educated response.

      Dr. Marvin

  3. Jason M. Bechtel Says: September 30, 2009 at 2:42 pm

    Dr. Marvin,

    Thank you for collecting some of the facts about Thimerosal. Unfortunately, despite the facts, your article makes illogical leaps, ignores some of the facts, and thence takes on an alarmist tone.

    As you explained, the mercury in Thimerosal is *ethyl* mercury, not “organic”/naturally occurring methyl mercury. The difference is significant. Ethyl mercury was chosen for Thimerosal because it is eliminated from the body much quicker than methyl mercury. After mentioning this distinction, the rest of your article ignores it and simply refers to “mercury,” which is disingenuous and insulting to the reader.

    When public health officials looked into the “mercury” content of vaccines in the late 1990s, they had to use the guidelines for *methyl* mercury because there were none for ethyl mercury. They found that the maximum exposure from all vaccines combined (187.5 micrograms) did not exceed the guidelines of the FDA or the Agency for Toxic Substances Disease Registry (ATSDR) for *methyl* mercury. It only exceeded the guidelines of the EPA.

    Also note that the average breast-fed baby ingests about 360 micrograms of *methyl* mercury in its first six months of life, *twice* the highest possible dose of the *ethyl* mercury in Thimerosal. There is also methyl mercury in water and in infant formula. It is an unavoidable natural substance.

    You state in your article that “mercury” has been “linked to” autism. This has since been scientifically discredited (the Wakefield article was nothing but speculation to begin with) and was partially the result of a broadening of the criteria for autism. Some people remain convinced of a link, however, due to the fact that the signs of autism usually become apparent during the second year of life, which is also when vaccines tend to be administered (producing the occasional anecdote of coincidental onset after inoculation). A study of children in Canada receiving vaccines over the years when the Thimerosal content varied (from 125 ug in 1987 to 225 ug from 1992-95 to *zero* ug since) found that the incidence of autism was higher in babies who received no Thimerosal in their vaccines whatsoever.

    To get to the point, I believe you are beating a dead horse. There is *no* *causal* connection between Thimerosal and autism. Ethyl mercury should not be conflated with methyl mercury. The amount of *ethyl* mercury in Thimerosal is a fraction of the quantity of the more dangerous *methyl* mercury that we all take in from the environment.

    More importantly, alarmist articles like this one endanger lives. They panic parents into withholding vaccines from their children, who are then subject to awful, sometimes fatal diseases, the horror of which people my age do not remember. No one has ever died from Thimerosal in vaccines, but people have died from influenza, measles, and the other diseases that vaccines had previously banished to the margins of civilization. Within months of parents withholding vaccines in England and Ireland, children were turning up in hospitals with measles. Three of them died.

    For other curious lay-persons (non-doctors) like myself, I recommend the book Vaccinated by Paul A. Offit, M.D. Chapter 10, “An Uncertain Future” reviews the history of this tragic confluence of media hype, attention-seeking behavior, and the natural human propensity for finding patterns even where there are none.

    I appreciate your general goal of eliminating needless toxins from our bodies. I just disagree that vaccines are a good way to pursue this goal. They save untold lives every day. Please don’t help to destroy one of our medical miracles with mere innuendo and hype.

    Jason M. Bechtel, MSBS

    • Jason, I appreciate your well-thought out response.

      While you are correct that I pointed to the differences between ethyl and methyl mercury (with Thimerasol containing ethyl mercury), the truth of the matter is that both ethyl and methyl mercury are organic forms of mercury (as stated in the CDC paper I referenced: “There are three forms of mercury. One form is an organic mercury, of which the two primary forms and ethyl and methylmercury. Ethylmercury is the form used in some vaccines.”). It has been “assumed” that ethyl mercury is excreted faster from the body, based on studies conducted on monkeys.

      Your comment and concern centers around the link between mercury and autism, although the article I wrote makes only one mention of autism and does not directly tie vaccinations to autism (as written in the article: “Organic mercury is a well-known neurotoxin that can accumulate in the body’s soft tissue, such as the brain, and has been linked to problems such as Alzheimer’s, dementia, autism, and much more.”) The fact is that no causal relationship has been scientifically proven between autism and anything; all relationships involving autism — including your argument that no relationship exists between mercury and autism — are assumptions. What we do know is that organic mercury is a neurotoxin and that ethylmercury — which is in Thimerasol — is one form of organic mercury.

      In 1999, after the 1997 FDA Modernization Act, the FDA “concluded that infants who received thimerosal-containing vaccines at several visits could exceed the total mercury exposure recommended by Environmental Protection Agency guidelines. These guidelines for exposure were set to avoid toxicity to the fetus.” By saying that the maximum exposure from vaccines “only exceeded the guidelines of the EPA” you’re saying that “2 out of 3 ain’t bad.” In actuality, the FDA acknowledged the guidelines set by the EPA and, in conjunction with the AAP, recommended that Thimerasol be removed from vaccines as a precautionary measure.

      In no way is the article meant to dissuade people from receiving vaccinations. The fact remains that people are concerned with the amount of mercury administered in vaccines. My article links to the Johns Hopkins report as a reference for people that have such concerns so they can be armed with the knowledge they need. Most vaccination clinics won’t know how much mercury is in a vaccine. This arms people with the knowledge they may be seeking. By providing the information, I hope people will also see that there are mercury-free vaccines available if that is what they are seeking.

      If the article sounds “alarmist” then I apologize. It is meant to provide information that is not readily available to those who are seeking it. It is not an article on the links between autism and ethylmercury. It’s an article referencing the amount of organic mercury in current vaccines with background information so people will know some of the controversy surrounding Thimerasol. Hopefully a safe, mercury-free alternative to Thimerasol will be developed soon. It’s something the FDA, CDC, and AAP have already called for, and something that will put this issue to rest for good.

      Dr. Marvin

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