Additives Found in Vaccines
- Millions of doses of vaccines are administered to children in this country each
year. Ensuring that those vaccines are potent, sterile, and safe may require the
addition of minute amounts of additives.
- Substances are added to vaccines to enhance the immune response, to prevent
microbial contamination, and to stabilize the vaccine formulation.
- The amount of additives found in vaccines is usually small.
Additives used in the production of vaccines may include:
- such as thimerosal or 2-phenoxy ethanol, are added to slow or
stop the growth of bacteria or fungi resulting from inadvertent contamination,
especially as might occur with vaccine vials intended for multiple uses or doses.
Stabilizers - such as lactose or monosodium glutamate (MSG), are added to
stabilize the vaccine formulation against a variety of conditions, such as temperature
variations or a freeze-drying process.
Adjuvants - such as aluminum hydroxide or aluminum phosphate, are added to
increase the ability of the vaccine to trigger, enhance, or
prolong an immune response.
Antibiotics - such as neomycin and streptomycin, are added to prevent the
potentially harmful growth of germs.
Other Substances - Vaccines may also include a suspending fluid such as sterile
water or saline. Vaccines may also contain small amounts of residual materials from the
manufacturing process, such as cell or bacterial proteins, egg proteins (from vaccines
that are produced in eggs), DNA or RNA, formaldehyde from a toxoiding process, etc;
while these materials are not "additives" per se, they may nonetheless be
present in vaccine formulations.
CDC, National Immunization Program: http://www.cdc.gov/nip
- All packaging for vaccines includes a package insert, which lists all ingredients
in the vaccine and discusses any known adverse reactions. To find out what additives
are in specific vaccines, ask your health care provider or pharmacist for a copy of
- Persons with a prior history of allergic reactions to any of the substances in a
specific vaccine should consult their health care provider before vaccination.
- To assure the safety of vaccines, the Centers for Disease Control and Prevention
(CDC), the Food and Drug Administration (FDA), the National Institutes of Health
(NIH), and other Federal agencies routinely monitor and conduct research to examine
any new evidence that would suggest possible problems with the safety of vaccines.
- To report a health problem that followed vaccination you or your provider should
call the Vaccine Adverse Event Reporting System (VAERS) at (800) 822-7967.
- All of the vaccines that are routinely recommended for infants, including
hepatitis B, haemophilus influenzae type b, DTaP, pneumococcal conjugate, IPV, MMR,
and varicella are available in formulations without thimerosal as a preservative.
FDA, Center for Biologics Evaluation and Research: http://www.fda.gov/cber/
Last updated: June 2001