The Great “Mercury/Vaccine” debate

“There is Mercury in vaccines!”

“Mercury is toxic!  I do not want it in my vaccines!”

This one is a personal pet peeve on mine…

So I have decided to do what any responsible healthcare professional would do…

Write a blog about it!

1st things 1st, some vaccines do contain mercury.  More specifically, some vaccines contain a substance called thimerosal (a type of mercury, but more on that later).     

Some vaccines contain thimerosal and some do not.  Recently, due to concerns regarding a potential link between thimerosal and autism (subsequent research has demonstrated that there is no link between thimerosal and autism.  A review of the most current medical literature on this topic can be found here: ), thimerosal was removed from the childhood vaccine schedule.  However, thimerosal can still be found in numerous vaccines across the globe.  So, should you be worried about thimerosal in vaccines? 

The short answer is NO.

The long answer is…well…still NO!

Thimerosal is an antiseptic/antifungal agent that is used as a preservative to prevent the growth of unwanted pathogens in multi dose injection vials (many vaccines are contained in multi dose injection vials).  Studies have revealed that the absence of a preservative (such as thimerosal) in a multi dose vial increases the occurrence of the growth of unwanted pathogens (such as Staphylococcus), that can then lead to infection or even (in some cases) death.  Additionally, thimerosal has become the preservative of choice because it does not affect the potency of the vaccine (many preservatives, other then thimerosal have a negative effect on the potency of the vaccine, rendering it less effective).    Vaccines are available in both single dose vials and multi dose vials.  Multi vials are typically used for large vaccine campaigns because they are much cheaper to produce then single dose vials, however due to trends/pressures upon the companies producing vaccines, more and more vaccines are now being offered in single dose vials.    

Mercury is a known neuro toxin.  However there are different types of mercury.  The 2 most relevant to our discussion are methylmercury and ethylmercury.  Methylmercury is type of mercury know to most people.  It is the type of mercury that is found naturally occurring in the environment (in fact whether you know it or not, you are exposed to mercury/methylmercury on a daily basis!  Mercury/methylmercury is found to be naturally occurring in water, soil, plants, etc), and is the type of mercury found in old-school blood pressure machines/thermometers.  Methylmercury is considered to be highly bio-available, meaning that it can be easily absorbed by the body (absorption is most effective via the gastro-intestinal tract).  Once absorbed, the amount of time to cause neuro toxicity depends on the amount and length of exposure.  Methylmercury itself is not toxic.  The human body is more than capable of metabolizing and excreting methylmercury.    However, once the exposure to methylmercury exceeds the body’s ability to metabolize and excrete the substance that is when it will begin to accumulate in the body and can then cause toxicity.    

Ethylmercury on the other hand has not been demonstrated to be toxic.  In fact, current research indicates that ethylmercury does not appear to be very bio-available, and thus the majority of the substance essentially passes right through the body without being absorbed.  The small amounts of ethylmercury that are absorbed are easily metabolized and excreted by the body, thus minimizing the potential for ethylmercury to accumulate in the body and thus lead to neuro toxicity.  Additionally the pharmacokinetic profile of methylmercury and ethylmercury are extremely different.  The half-life of methylmercury is approximately 1.5 months, versus ethylmercury which is less than a week.

It should also be mentioned at this point that the main/most effective means for mercury to be absorbed by the human body is via the gastrointestinal tract.    

So, can you guess which type of mercury is in (some) vaccines?

I will give you a hint…

It starts with Ethyl…

And ends with Mercury…

That is right!  Vaccines contain ethylmercury (the “safe” kind)!  

Ethylmercury is an end product of the metabolism of thimerosal.  Vaccines contain 25 to 50 micrograms of thimerosal/ethylmercury (the “good” kind of mercury) per dose (depending on the type of vaccine).  For a comparison a can of tuna contains 10 to 100 micrograms of Methylmercury (that “bad” kind of mercury).  Depending on which source you read, you can safely consume that amount of tuna 2 to 3 times per week.  Again that is per week, everyday of your life! 

Considering all of the above information, at the end of the day, what is the take home message of the above post?

Yes, some vaccines do contain mercury.  However, the vaccines that do contain mercury contain a “safe” type of mercury (ethylmercury) that is easily excreted from your body.  The method of administration (injection) of vaccines diminishes the body’s ability to absorb what “safe” mercury that you are exposed to.  Additionally, the amount of “safe” mercury contained in a single vaccine dose is comparable to eating a couple of cans of tuna a week (even less so considering the pharmacokinetic profile of methylmercury and ethylmercury as discussed above), and this does not even take into consideration the amount of “bad” mercury you are exposed to on a daily basis as a result of normal environmental exposure.

I should mention here that I have chosen not to address the “issue” of whether or not vaccines are effective.  It is my personal and professional opinion that vaccines are extremely effective!  However that is a separate topic for another day/blog post.  I wanted this blog post to address the “issue” of mercury in vaccines, separate from the discussion of whether or not vaccines are an effective healthcare tool/treatment (again, it is my personal and professional opinion that they are). 

This has been the skeptical samurai

Working to serve through the process of inquiry


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