Thimerosal is a mercury-based preservative used in the manufacturing process of “multi-dose” vaccines. It helps to prevent the growth of bacteria and fungi in vaccines and is necessary to stabilize and sterilize the vaccine and also to prevent infections at the vaccination/injection site. Single-dosed vaccines do not require a preservative/stabilizer.
Science to date has concluded that there is NOT a link between vaccines containing thimerosal and autism or any other neurological or behavior disorder. Further, the National Advisory Committee on Immunization (NACI) has reviewed all current evidence and concluded that “there is no legitimate safety reason to avoid the use of thimerosal-containing products for children or older individuals, including pregnant women”
Thimerosal will continue to be used in multi-dosed vaccines until a safe and effective alternative is found. For a complete list of vaccines containing thimerosal, check the Public Health Agency of Canada website: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/07vol33/acs-06/index-eng.php