Vaccine
Additives
Vaccines often contain antibiotics as well as
preservatives to prevent bacteria from growing, stabilizers to
maintain the vaccine's effectiveness, and adjuvants to stimulate
production of antibodies. Although present only in minute amounts,
these additives play an important role in vaccines. Some vaccine
additives, such as thimerosal, aluminum, and formaldehyde, are
controversial.
Antibiotics
Antibiotics prevent germs from growing in the vaccine
cultures. Neomycin is commonly used, but penicillin and related
antibiotics are not used in vaccines because many people are allergic
to them.
Preservatives
Vaccine vials that contain several doses need
preservatives because each time a needle enters the vial there is a
risk of contamination. Thimerosal is an extremely good preservative,
but it is controversial because almost half of its contents is
mercury, which is known to cause developmental problems in children
when taken in large enough quantities. Formaldehyde, or formalin, is
used to inactivate the polio vaccine virus in IPV and to kill germs
in the cultures used to produce other vaccines.
Stabilizers
Stabilizers maintain vaccine effectiveness despite
heat, light, or other adverse conditions. Sulfites and monosodium
glutamate (MSG), also found in many foods and alcoholic beverages,
are used to stabilize some vaccines.
Adjuvants
Aluminum, in the form of aluminum gels or salts of
aluminum, is added to vaccines to help prompt antibodies to respond.
For example, tetanus and diphtheria toxoids and pertussis vaccine are
bound to aluminum salts.
