Ingredients in Vaccines
The main ingredient in a vaccine is the weakened, killed, or portion of the germ (antigen). Other ingredients may be added to a vaccine besides the weakened or killed antigen. Most of these ingredients are present in very low amounts which is very important.
Some of these ingredients include:
- Preservatives: Preservatives are added to vaccines to prevent contamination.
- Adjuvants: Adjuvants are added to a couple of the CDC vaccines (not all); they are used to help create a better immune response. They help make a faster, more potent response.
- Stabilizers: Stabilizers ensure that even if the vaccine is exposed to light, heat, acidity or temperature, that it remains the same.
- Antibiotics: Antibiotics may be added to some vaccines to prevent contamination of the vaccine (prevent bacteria from growing in the vaccine).
- Inactivating ingredients: These ingredients kill or inactivate a virus.
- Manufacturing byproducts, such as cell culture materials: These materials are used to grow the antigenic portion of the vaccine.
Examples of these materials include aluminum salt (adjuvant), egg protein (cell culture material), formaldehyde (inactivating ingredient), monosodium glutamate or MSG (stabilizer), thimerosal (preservative).
Thimerosal is a compound containing ethylmercury. It is important to note that ethylmercury is NOT the same as methylmercury. Methylmercury is the component found in fish. At high levels, this compound may be toxic. However, ethylmercury is cleared from the human body faster than methylmercury, making ethylmercury SAFE for the human body.
Thimerosal is added to a vaccine to help prevent germ growth.
Thimerosal was taken out of all childhood vaccines in the United States in 2001. The only vaccine offered today in the United States that contains thimerosal is one version of the flu vaccine.
It is important to note that while some vaccines may have small amounts of antibiotic, no vaccine in the United States contains penicillin as an antibiotic because of its potential to induce an allergic reaction.
All of the ingredients in vaccines are contained in small or trace amounts meaning that they are safe for human use.
Image Source: CompoundChem
Centers for Disease Control and Prevention - Making the Vaccine Decision: Addressing Common Concerns