Thimerosal is used a preservative in
order to prevent the growth of dangerous microbes in case of contamination in
mulit-dose vaccines. When each new needle is inserted to the vial. The
thimerosal prevents contamination in in the vial when doses are drawn out. This
is very important because if someone were to receive an injection that was
contaminated it could potentially be very deadly (1).
Thimersosal has been used as a
preservative in vaccines since 1940’ (J)s. However, since 1999 thimerosal has
only remain in one type of vaccine. Which is the multi-dose Flu vaccine. The
FDA decided to this in order to limit the amount of mercury (ethylmercury)
children were exposed to, in other words it was a precautionary measure (1).
However, there were concerns in the
media about the potential of mercury toxicity from multiple injections in the
first few 6 months of life (J). However, people mistook the compound that
thimerosal has called ethylmercury from methylmercury. While the two are related
they have differences (3).
Methylmercruy is more toxic. It is
able to pass the blood brain barrier and damage the nervous system since it is
small in size (CHOP). It also has a longer half-life and more lipophilic so the
body has a harder time excreting it from the body (3).
On the other hand, ethylmercury has a
shorter half-life and the body is able to excrete much faster. It also does not
accumulate in the body. Nor does it disease and because of it is bigger in size
it is unable to cross the blood brain barrier so it is not able to damage the
nervous system (2, 3).
There were also many reputable studies
conducted that have yet to show any link between mercury in vaccine causing
autism in children. Different methods have methods have been used and some
examined rates of autism in a state or country and compared the rates of autism
before and after thimerosal was removed. The results showed that the number of
children diagnosed with autism has not gone down since the removal of
thiemrosal from vaccines (1).
Resources:
- Centers for Disease Control and Prevention. (2013, February). Understanding Thimerosal, Mercury, and Vaccine Safety. Retrieved May 5, 2020, from https://www.cdc.gov/vaccines/hcp/patient-ed/conversations/downloads/vacsafe-thimerosal-color-office.pdf
- Children's Hospital of Philadelphia. (2014,
November 5). Thimerosal. Retrieved May 6, 2020, from https://www.chop.edu/centers-programs/vaccine-education-center/vaccine-ingredients/thimerosal
- Clift, K., & Rizzolo, D. (2014). Vaccine myths and misconceptions. Journal of the American Academy of Physician Assistants, 27(8), 21-25. doi:10.1097/01.jaa.0000451873.94189.56
