Thimerosal is a mercury-containing preservative that is used to prevent the growth of bacteria and fungi in vaccine vials that contain many doses of vaccine. Thimerosal used in the vaccine manufacturing process can be present in trace amounts in the final product.
Vaccines that contain trace amounts of thimerosal include Influenza and Hepatitis B vaccines. There are two types of mercury:Methylmercury- found in the environment through weathering of rocks, burning of coal, and volcanic eruptions. It makes its way through the food chain in fish, animals, and humans. In high levels it can be toxic to people.
Ethylmercury -found in thimerosal. Studies suggest that it is broken down and passes through the body very quickly before it can do any harm. Studies have also shown it does not accumulate in the body.
The National Advisory Committee on Immunization (NACI) has reviewed the current scientific proof on the use of vaccines containing thimerosal and concluded that there is no legitimate safety reason to avoid the use of thimerosal-containing vaccines. Scientific evidence has not shown a relationship between thimerosal in vaccines and autism or other neurodevelopmental diseases.
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