Safety > Issues of Interest > Thimerosal
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You Should Know
is a preservative which contains a type
of mercury called ethylmercury. Thimerosal
has been used in some vaccines and other
products since the 1930's to help keep
them safe by preventing bacterial contamination.
of mercury exposure from vaccines is low.
There is no evidence to suggest that thimerosal
in vaccines causes any health problems
in children and adults other than minor
reactions like swelling at the injection
1999 the Public Health Service (PHS) agencies
and the American Academy of Pediatrics
(AAP) recommended that thimerosal be taken
out of vaccines as a precautionary measure.
recommended licensed vaccines that are
currently being manufactured for children
in the U.S. [except some influenza (flu)
vaccine and Td (tetanus-diphtheria) vaccines]
contain no thimerosal or only trace amounts.
is a metal that occurs naturally and is
found everywhere in the environment. There
are different types of mercury. Thimerosal
contains approximately 49% ethylmercury.
mumps, and rubella (MMR), varicella (chickenpox),
and inactivated polio vaccine (IPV) have
never contained thimerosal.
a report by The Institutes of Medicine
(IOM) concluded that there is no association
between autism and vaccines that contain
thimerosal as a preservative.
is accumulating of lack of harm resulting
from exposure to thimerosal in vaccines.
- A recent
study conducted by the National Institute
of Allergy and Infectious Diseases (NIAID)
concluded that mercury levels in the blood
of babies that received vaccines with thimerosal
remained well below levels considered acceptable
by the EPA. Furthermore, ethylmercury (thimerosal)
seems to be removed from the body quickly
through the gastrointestinal tract (stools).
- CDC recently
conducted a study to see whether there are
associations between vaccines containing
Thimerosal as a preservative and a wide range
of neurodevelopmental disorders. Results
found no consistent significant associations.
Studies to examine these issues are ongoing.