1. • A previous episode of anaphylaxis attributed to thimerosal is an absolute contraindication to the use of thimerosal-containing vaccines.

2. Issues that have been reviewed include the role of thimerosal (in hepatitis B vaccine) in acute lymphoblastic leukemia.

3. Dental Amalgams are an important source of mercury vapour and the vaccine preservative thimerosal is a significant source of ethyl mercury

4. Thimerosal is added to vials of vaccine that Contain more than one dose (multi-dose vials) to prevent growth of germs, like bacteria and fungi