Does a flu shot have mercury in it?

Multi-dose vial, yes: Thimerosal is a mercury based preservative that is in some vaccines, including flu shots packaged as a multi-dose vial. Individually packaged single-dose shots do not have preservatives. The nasal spray flu vaccine also does not contain thimerosal. The thimerosal in shots was a tiny amount, and has been removed from children's vaccines, but was not shown to be harmful to people receiving vaccines.

Yes But...: See dr kwok's response. But keep in mind that the type of mercury ( and there safe and not safe types) in the shot has been demonstrated in many, many research studies to not have or cause any serious side effects in babies whereas the influenza infection can be deadly, causing unfortunately several thousands deaths in children per year. Do not be afraid. Get the shot!