Vaccinate Your Baby

About Vaccines

  • Types of Vaccines
  • Influenza (Flu) Vaccines
  • Importance of Timing
  • Vaccine Production
  • Ingredients


Vaccines are made up of small amounts of the bacteria, virus or other antigen and administered to stimulate the immune system to create antibodies to prevent future infections with the disease. Like many of the foods we eat, small amounts of chemicals may be added to the vaccine's formula to preserve or improve its effectiveness and keep it sterile.

Sometimes a child may be sensitive to one of the components of a vaccine, and an allergic reaction may result. For this reason, you should discuss any allergies your child may have with your health care provider.

Recently a small group of very vocal but misinformed individuals have made accusations regarding the safety of vaccines, claiming that vaccines contain a laundry list of toxins. In many instances these allegations are completely incorrect. In others, the claims are taken out of context.


The first thing that you have to consider in any discussion about so called toxins in vaccines is that everyday compounds can be either beneficial or toxic depending on the quantity used. For example, let's consider water. No one would deny that it is important to drink plenty of water to remain healthy. But did you know that drinking too much water can kill you? While normal, healthy people have little to worry about, we still occasionally read stories about people actually dying from excess water consumption. But don't panic, usually this happens under extreme circumstances, like following long bouts of sweating due to intensive exercise or exposure to very hot days.

A second mistake that people make when looking at ingredients in vaccines is that the whole doesn't always equal the sum of its parts. A simple example of this theory can be found in the example of everyday table salt. Table salt is made of two very dangerous elements, chlorine and sodium. Chlorine is a dangerous gas; sodium is a highly reactive element that explodes when it comes into contact with water. Yet if you combine these two dangerous elements you get a very safe compound, simple table salt.

So before you classify a component as a 'toxin,' you must consider more than whether or not it is simply "in there." You have to look at the quantity, how it is used, whether it is combined with some other element, whether it is used as part of the production and then stripped back out, and many other factors.

Vaccines may include:

  • Preservatives and stabilizers: Since 1968 the United States Code of Federal Regulations (the CFR) has required, in general, the addition of a preservative to multi-dose vials of vaccines; and worldwide, preservatives are routinely added to multi-dose vials of vaccine. Tragic consequences have followed the use of multi-dose vials that did not contain a preservative (including deaths) and have served as the driving force for this requirement.
  • Thimerosal: A commonly known preservative thimerosal, was at the center of controversy a few years ago. Thimerosal, an ethylmercury based preservative, was phased out of vaccines in the late 1990s in an effort to reduce the overall burden of mercury from all environmental sources. Unlike the methylmercury found in the environment, however, ethylmercury is quickly excreted from the body. Numerous studies have shown that autism rates are no lower in children who received vaccines without thimerosal than those who did. Today, influenza is the only vaccine that still contains thimerosal as a preservative, and there is a thimerosal-free formulation available for administration to children.
  • Formaldehyde: may be used as an antimicrobial. Formaldehyde effectively inactivates the organisms and biological substances used in vaccines. Formaldehyde is present in the environment and is a byproduct of metabolism so it is already present in the human body.
  • Adjuvants: Aluminum has been used in some vaccines for over 75 years to improve the vaccine's performance by helping to stimulate the body's immune system to produce antibodies. Without the use of an adjuvant we would need to administer more shots in a given vaccine series or face lower immunity and less protection from the disease. Aluminum is also commonly found in food, water, infant formula and even breast milk.
  • Egg Protein: Some vaccines are prepared in eggs. If your child has had an allergic reaction to eggs or egg products, you should be sure to discuss this with your child's doctor.

In addition to these ingredients you may have heard that vaccines contain products such as antifreeze and other outrageous components. This is not true. The claim of antifreeze being in vaccines comes from the use of polyethylene glycol in one brand of the flu vaccine to inactivate the virus. It is also used to purify certain vaccines. But polyethylene glycol is not antifreeze; it is just a component that is found in antifreeze, just as water is a component. Polyethylene glycol has a low toxicity,* and is used in a variety of products. It is the basis of a number of laxatives and skin creams, and is used as an irrigating solution in surgical procedures and in drug overdoses.

* Victor O. Sheftel (2000). Indirect Food Additives and Polymers: Migration and Toxicology. CRC, 1114-1116.

Additional Resources

  • Vaccine Ingredients: What you should know (Also available in Spanish)
  • Questions and Answers about Vaccine Ingredients


Learn More

  • American Academy of Family Physicians
  • American Academy of Pediatrics
  • American Medical Association
  • Autism Science Foundation
  • Centers for Disease Control and Prevention
  • Emory Vaccine Center
  • Every Child By Two
  • Families Fighting Flu
  • The History of Vaccines
  • Immunization Action Coalition
  • Johns Hopkins Institute of Vaccine Safety
  • Meningitis Angels
  • National Foundation for Infectious Diseases
  • National Meningitis Association
  • National Network for Immunization Information
  • Parents of Kids with Infectious Diseases
  • Shot By Shot
  • The Vaccine Education Center at the Children's Hospital of Philadelphia
  • Voices for Vaccines
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