The medical journal The Lancet has retracted a controversial study that linked the measles, mumps, and rubella (MMR) vaccine to the development of autism and gastrointestinal disorders. When the study was first published, many experts called it "shoddy science," though it caused widespread concern among parents. In fact, vaccination rates in both Great Britain and the United States fell in response to the study's publication. Vaccine experts say the retraction by the prestigious medical journal...