Does the new vaccine contain the mercury compound thimerosal?
Flu vaccine packaged in a multidose vial contains thimerosal, a preservative that prevents contamination of the vial during repeated use. One dose from a multiuse vial contains about 25 micrograms of mercury. By comparison, a tuna fish sandwich contains about 28 micrograms of mercury. Repeated studies have shown thimerosal to be safe. However, people who want to minimize mercury exposure can ask for a vaccine in a single-dose package, which has only trace amounts. Thimerosal is not used in the production of the nasal spray vaccine.