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Vaccine Safety For Information Purposes
June 24, 2005
La Marque
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A recent news report
has questioned the safety of vaccines containing the preservative Thimersol.
The Texas Department
of State Health Services (DSHS) has issued a statement regarding the
safety of vaccines containing Thimersol. The statement below also
contains links to additional information on the subject.
June
22, 2005
Thimerosal is a preservative that was a component of some
vaccines. It was used to prevent microbial contamination of multi-dose
vials of vaccines, dating back to the 1930’s. In 1999, the U.S. Public Health
Service called for the removal of thimerosal from recommended childhood vaccines
as a precautionary measure since it contains ethylmercury (50% by weight).
Little is known about ethylmercury. Its properties are different from
methylmercury, the more common form of organic mercury that, in high doses, can
adversely affect the nervous system. Other than local injection site
reactions such as redness or swelling, no known harmful health effects can be
attributed to thimerosal levels in vaccines. Vaccine manufacturers have
either removed thimerosal entirely or reduced it to only trace amounts in the
recommended childhood vaccines. Since methylmercury, the type of mercury
commonly found in the environment, can cause neurodevelopmental delays in
infants exposed to high levels, some hypothesized thimerosal could cause
neurodevelopmental disorders such as autism. However, high doses of
methylmercury have not been linked to autism. Autism is a complex and
often severe neurological disorder with a broad range of characteristics, most
notably developmental delays and language, communication, and social deficits.
The Institute of Medicine (IOM) recently
published a report: Immunization Safety Review 2004: Vaccines and Autism.
The review concluded that thimerosal-containing vaccines were not associated
with autism, and reaffirmed the lack of association between
measles-mumps-rubella (MMR) vaccine and autism, which was concluded in an
earlier IOM report. A 2001 IOM report on thimerosal-containing vaccines
and neurodevelopmental disorders concluded that there was not enough evidence
for an association between thimerosal-containing vaccines and autism and other
disorders. Population based research studies published since 2001 have not
revealed an association between thimerosal-containing vaccines and autism in
children. In addition, a review published in Pediatrics (Parker SK, et al.
Pediatrics 2004 Sep; 114(3): 793-804) concluded that the body of scientific
research does not support a link between thimerosal and autism.
Links to additional
information:
The Texas Department of State Health Services Immunization Branch website
provides information on vaccine safety and numerous links to additional
resources. This information may be accessed at:
http://www.tdh.state.tx.us/immunize/vac_safety.htm. The Immunization
Branch may also be contacted by calling (800) 252-9152.
For More Information Contact:
Brian Rutherford
Public Health Planner
Galveston County Health District
(409) 938-2275
brutherford@gchd.org
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