Fact: Vaccine ingredients are not harmful in humans or animals, with the exception of the very rare allergic reaction.
Why the Myth Exists
The vaccine package inserts include all kinds of ingredients. It is easy to see this list of cells, metals, and chemical names, and become alarmed.
Variations on this Myth
- “Vaccines contain deadly neurotoxins.”
- “Vaccines contain deadly carcinogens.”
- “Vaccines contain antifreeze / insecticides / fertilizer.”
- “Vaccines contain aborted human fetal tissue.”
Examples Found Online
The Real Deal: What the Evidence Shows
Vaccine ingredients are not harmful in humans or animals, with the exception of the very rare allergic reaction to gelatin or egg proteins.
Vaccines makers strive to create the strongest immune response using the minimum number of antigens and the lowest quantity of additional ingredients.
Vaccines do not contain fetal tissue, antifreeze, fertilizer, or insecticides. They also do not contain any ingredients in sufficient quantities to be concerned about neurotoxicity (“harmful to the brain”) or carcinogenicity (“cancer-causing”).
Anything is toxic and harmful at a certain dosage, even water. Vaccine ingredients are nowhere near those dosages!
Any given vaccine may contain a handful, but not all, of these ingredients. Several ingredients listed below have full pages devoted to them on this site.
Antigens are the antibody-generating ingredients that trigger our immune system to create memory cells and antibodies for a specific pathogen. They are killed, fragmented, genetically modified, or cultured in a way that makes them unable to reproduce in humans (and thus unable to cause disease).
- Attenuated live viruses (weakened to the point they cannot reproduce in a human)
- Killed viruses
- Partial viruses
- Partial bacteria
- Toxoids (inactivated toxins)
Inactivating ingredients kill pathogens or detoxify bacterial toxins during vaccine production. Some tiny amount may remain in the vaccine.
- Formaldehyde | More about formaldehyde in vaccines >
- Polyethylene glycol
Antibiotics prevent bacterial contamination while the vaccine is being made. Vaccine makers only use antibiotics that are far less likely to provoke a reaction. Some trace or undetectable amount may remain in the vaccine.
- Polymyxin B
- Gentamicin sulfate
Preservatives prevent bacterial or fungal contamination during vaccine storage, particularly in multidose vials in which a syringe enters more than once. Multidose vials are no longer commonly used in the United States.
- Ethyl mercury (in thimerosal) | More about mercury in vaccines >
Adjuvants agitate tissues to increase and speed up the immune response, making the vaccine more effective. This allows vaccine makers to reduce the number of antigens and doses required to confer immunity.
- Aluminum salts | More about aluminum in vaccines >
- Squalene (not used in vaccines in the United States)
- Polyethylene glycol (not used in vaccines in the United States)
Stabilizers prevent the chemical reactions that might separate vaccine components, change the pH, or increase a local reaction. They also make vaccine less sensitive to temperature changes.
- Monosodium Glutamate (MSG)
- Albumin (derived from human blood)
The vaccine virus or bacteria is usually grown in a cell culture. The culture provides food or living quarters for the pathogen, derived from chicken eggs, yeast, bovine extract, or monkey kidney cells, etc. No whole cells or tissues end up in the vaccine. Only tiny amounts of DNA fragments (nucleotides) or proteins may remain.
- Egg proteins
- Yeast proteins
- Animal cell DNA fragments
- Human fetal cell DNA fragments
References and Further Reading
- “Immunization Basics: Vaccine Additives and Preservatives” | Vincent Iannelli, MD | verywell
- “Simple Math – the Dose Makes the Poison” | The Skeptical Raptor
- “Addressing Parents’ Concerns: Do Vaccines Contain Harmful Preservatives, Adjuvants, Additives, or Residuals?” | Paul A. Offit, Rita K. Jew | Pediatrics
- “How a Vaccine Is Like a Banana — and Why That’s Good” | Jeffrey Kluger | Time
- “What Goes Into a Vaccine?” | PublicHealth
- “Toxic Myths About Vaccines” | Dr. David Gorski | Science-Based Medicine