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Vaccine Ingredients

Do vaccines really contain the horrifying poisons claimed by antivaccine activists?  

by Brian Dunning

Filed under Alternative Medicine, Conspiracy Theories, General Science, Health

Skeptoid Podcast #180
November 17, 2009
Podcast transcript | Download | Subscribe
Also available in Chinese | Russian



Today we're going to point our skeptical eye at some of the claims made by antivaccine activists, in particular, their lists of frightening chemicals and other dangerous toxins they say are included in vaccines. As it's an important topic and is increasingly in the public eye, we don't want to dismiss these claims out of hand. Rather, we want to have a handy working knowledge of the basics so we're better prepared to deal with such rhetoric when it comes up.

You don't have to go to the antivaccine websites to find this horrifying list of witch's-brew ingredients. The Centers for Disease Control publishes a detailed list of every additive in every vaccine, sorted both by ingredient and by vaccine. I run my eye down this official list: formaldehyde, aluminum phosphate, ammonium sulfate, bovine extract, thimerosal, amino acids, even monkey kidney tissue. This list is published by the very same government that's assuring us these vaccines are safe. How can that be? Does this mean the antivaccine activists are right, and vaccines are indeed loaded with deadly toxins?

This is a case where cooler heads need to prevail. First, let's start with the premise that every cell of your body is made up of a huge number of chemical compounds, all of which have scary-sounding chemical names. Therefore, we can derive that scary-sounding chemical names, by themselves, are not to be feared. Cooler heads might choose to allow for the possibility that these scary chemicals are added to vaccines because they serve some useful purpose.

When you're exposed to a pathogen, it irritates your body. This irritation is what provokes your immune system to respond, and produce antibodies to fight the pathogen. Vaccines work the same way. They simulate the pathogen in order to produce to right irritation. To prepare your body with the right antibodies to fight some anticipated future pathogen, it's a necessary and expected step for the vaccine to provoke your immune system with a carefully planned challenge. So when you hear antivaxxers charge that vaccines are harmful and irritating, that's quite true, but it's for an important reason and it's very deliberately controlled. This attack on your body to provoke an immunological response is the way vaccines work. It's the way your immune system rolls. You don't strengthen your immune system by eating vitamins or drinking wheatgrass juice or doing yoga or having a coffee enema; you strengthen it by challenging it to respond.

So now that we understand that a vaccine is not pretending to be a shot of Mickey Mouse sunshine, let's take a look at some of these frightening sounding ingredients:


Absolutely true. Formaldehyde sounds scary because we see dead animals preserved in jars of it in museums. One of its uses is to sterilize things, and this is why small drops of it are added to some vaccines. Without such sterilization, a vial of vaccine might become contaminated while it's sitting on the shelf. Formaldehyde is used because it's naturally found in the human body, as it's a normal byproduct of digestion and metabolism. When you receive a vaccine shot that was sterilized with formaldehyde, you already have much more of it in your body than you get from the shot. All of this formaldehyde is easily broken down chemically simply because your body is an aqueous environment, and it's harmlessly discharged every day.


This one is simply untrue. Antifreeze, the poisonous substance used in your car's engine, is ethylene glycol. Because it's so poisonous, antifreeze is not used in food processing or medical equipment, and certainly not in vaccines or other drugs. A less toxic form of antifreeze is propylene glycol, which is not in vaccines either. What is used in some is 2-phenoxyethanol. It's an antibacterial agent used in many vaccines to sterilize them, and also used in wound care as a topical antibacterial. The confusion with antifreeze probably comes from the fact that both are part of the glycol ether family of hydrocarbons, but they are not the same thing.


This is the most common claim, and it's the one you've probably heard the most about, so I won't spend much time on it. Some vaccines (but no scheduled childhood vaccines) are preserved with thimerosal, which contains ethylmercury. Elemental mercury is a dangerous neurotoxin, but when it's bound as an organic ethyl, it's easily filtered out of your body by your kidneys and is quickly discharged. This is one reason thimerosal has always been such a safe and popular preservative, and it's still found in many products. Mercury can also be bound as a methyl, which is different, and is much harder for your body to filter out. But fear not; no vaccines or thimerosal ever contained methylmercury, and this scaremongering has no plausible foundation.

Latex Rubber

This one is also completely untrue. Latex is not, in any way, part of any vaccine, and never has been. The source of this claim is the fact that a lot of medical equipment, like syringes and packages, contain latex. Alternatives are always available for people with severe latex allergies. This is a common issue for such people, and has no specific relevance to vaccines whatsoever.

Hydrochloric Acid

Scary sounding, and true. If you pour hydrochloric acid on your skin, you get burned, because your skin is pH balanced. But if you add acid to something that's alkaline, acid brings it back into balance. Hydrochloric acid is used in many industries to bring compounds that are too alkaline to the desired pH level, and the pharmaceutical industry is no different. Some vaccines, once the active ingredients are all added, may be too alkaline; and if injected like that, would cause an adverse reaction. Hydrochloric acid brings the vaccine down to your body's normal pH level of about 7.4. Hydrochloric acid is also the primary digestive acid produced in your stomach, so it's no stranger to the human body.


Aluminum, in various forms, is added to vaccines as an adjuvant. An adjuvant is like a catalyst for the desired irritation, making the challenge even more annoying for your body. It's supposed to be there, on purpose, to make your body react even more strongly. More antibodies are created as a result of the more provocative challenge. Remember: Mickey Mouse sunshine and roses do nothing.

Aluminum is, of course, a neurotoxin, but only at amounts far, far higher than that normally found in our bodies, in the environment, and certainly in vaccines. Just by living and breathing on a planet like Earth where aluminum is the third most abundant element, the average person consumes 3-8mg of aluminum per day, of which less than 1 percent is absorbed into the blood. Vaccine doses are allowed to contain a maximum of .85mg of aluminum; so the maximum dose of aluminum in a vaccine is about the same as the maximum that might get into everyone's blood in a normal day (about what's contained in 33 ounces of infant formula). Most vaccines contain less than this. Studies have proven no difference in neurological condition between children who have had aluminum adjutated vaccines and those who have not.


Once again: FAIL. Completely untrue. Although any search of the web would have you believe otherwise: The phrase "aspartame in vaccines" is all over Google. So what are these vaccines? I searched the CDC's database of vaccines; nothing. I searched the database of additives; still nothing. I only found only antivax article that mentioned specifically which vaccine aspartame is in, and it claimed only one: The typhoid vaccine Typhim Vi. But it's not true. The additives in Typhim Vi are publicly available and aspartame is not on the list. This is when the antivaxxers are at their worst, when they simply make up lies. This is not constructive for any purpose.

Aborted Fetal Tissue

They sure picked the scariest sounding thing they could think of here! Although this specific ingredient is made up, vaccines can include all sorts of proteins derived from all sorts of animals.

Human Serum Albumin, or HSA, is a stabilizing protein made from human blood donations, not from aborted fetuses. Bovine albumin is also used in a few vaccines. Some vaccines are grown in cultures of monkey or chicken kidney tissue, and when the vaccines are extracted, a few cells from the culture always remain. There's never been any evidence that this might be dangerous. Some vaccines are cultured inside chicken eggs, and some egg protein may remain as a result. This can be a problem for people with severe allergies to egg protein, so these people should avoid these vaccines.

You'll hear all sorts of shock stories about embryonic fluid and cells of exotic animals. Be skeptical of such stories, and you are shocked and concerned, spend five minutes searching the web to find out if that ingredient is actually used; and if so, why; and whether it represents any credible cause for concern. I guarantee you that Jenny McCarthy is neither the first person, nor the best informed, to have considered vaccine safety.

Live Viruses

Some viruses don't retain their chemical markers well enough when they're dead in order for the immune system to recognize them, so a very few vaccines are given with the viruses still alive. Formaldehyde is usually used to knock them out, weakening them to the point where they no longer pose a threat, but still alive enough to provoke the desired response. This is not done haphazardly: Finding just the right balance for the vaccine to be effective but not dangerous is hard work.

You'll hear antivaccine activists shout "Green our vaccines!" What do they mean? Are vaccines environmentally unfriendly? What does "being green" have to do with it? Presumably this is a swipe at vaccine additives which they believe are unsafe or damaging to the environment. Sadly it's too vague of a charge to answer directly. Specific claims can be tested; vague rallying cries cannot. This is where the antivaxxers' movement has taken them: Whenever they've attempted to levy a specific, testable claim, it's easily falsified. Don't let a sound byte as meaningless as "Green our vaccines" carry any clout it has not earned.

Many antivaccine activists believe that a healthy diet is all that's needed to guard against disease. Unfortunately, a healthy diet by itself does not present any immunological challenges. No antibodies are created as a result. Then when a pathogen enters the body, the pathogen wins, and the body becomes diseased. If you focus on your diet or your fitness, but ignore your immune system, expect to look slim and run marathons, but don't expect your immune system to be well prepared should you be unlucky enough to run into polio.

By Brian Dunning

Please contact us with any corrections or feedback.


Cite this article:
Dunning, B. "Vaccine Ingredients." Skeptoid Podcast. Skeptoid Media, 17 Nov 2009. Web. 24 Mar 2017. <>


References & Further Reading

AAP. "Vaccine Ingredients." Immunization. American Academy of Pediatrics, 20 Jan. 2011. Web. 25 May. 2011. <>

CDC. "Ingredients of Vaccines - Fact Sheet." CDC. U. S. Federal Government, 19 May 2009. Web. 11 Feb. 2010. <>

Janeway, C., Travers, P., Walport, M., Shlomchik, M.J. Immunobiology. New York: Garland Publishing, 2001. 582-583.

Marshall, Gary. The Vaccine Handbook. West Islip: Professional Communications, Inc., 2008.

Ragupathi G., Yeung K., Leung P., Lee M., Lau C., Vickers A., Hood C., Deng G., Cheung N., Cassileth B., Livingston P. "Evaluation of widely consumed botanicals as immunological adjuvants." Vaccine. 2 Sep. 2008, 26(37): 4860-4865.

Ribeiro C., Schijns V. "Immunology of vaccine adjuvants." Methods Molecular Biology. 1 Jan. 2010, 626: 1-14.


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