Adverse publicity that placed undue emphasis on a possible connection between autism and the measles-mumps-rubella (MMR) vaccine and vaccines containing thimerosal made parents in the United Kingdom reluctant to allow their children to receive the vaccine. The same concerns have played themselves out in the U.S. Food and Drug Administration's decision to recommend removal of thimerosal from other vaccines, even as the individual autism claims have been rejected. That recommendation, based on unsubstantiated safety concerns, reveals a deep-seated institutional overreaction that is more likely to cost lives than to save them.