Vaccines are overwhelmingly safe, but in a few very rare instances, they can have unintended side effects. The National Vaccine Injury Act of 1986 provides a federal cause of action for parents whose children have been injured by vaccines.
The Paluck family sued the Secretary of Health and Human Services for compensation over a claim that an MMR vaccine caused infant K.P. to lapse into a "severe neurological disability." After the case bounced around the court system for a bit, the Court of Federal Claims vacated a special master's determination that K.P.'s deterioration wasn't caused by the vaccination. The Federal Circuit affirmed.