Since it's flu season, it's a good time to clear up concerns people might have about mercury. This topic comes up as some parents inquire about the safety of flu shots and, in particular, about thimerosal. This is a kind of mercury used in very small amounts as a preservative in most flu vaccines.
In the late 1990s, the U.S. Public Health Service, the American Academy of Pediatrics and vaccine makers agreed to eliminate or reduce using thimerosal in vaccines for kids as a precautionary measure. Today, almost all the childhood vaccines sold in the United States have no thimerosal or only trace amounts. The only exception is the flu vaccine.
But research shows there is no reason to worry about getting a flu shot with thimerosal. The known health risks from mercury mainly come from a type called methyl mercury. Thimerosal contains ethyl mercury, a different form of the chemical. Ethyl mercury is processed by the body differently and leaves the body faster.
The important thing to know is that "there is no convincing evidence of harm" caused by the small amount of thimerosal in flu shots, according to the Centers for Disease Control and Prevention. The most you need to worry about is a little swelling and redness at the injection site due to sensitivity to thimerosal. Drug companies make a small number of flu shots without thimerosal each year and plan to make more in the future.
So don't let worries about mercury stop you from making sure that both you and your kids get a flu shot this year. Still have questions? Learn more about flu vaccines and thimerosal from CDC.