The U.S. Supreme Court ruled Tuesday that drug makers cannot be sued over side effects from vaccines, a decision that could have implications for those who believe there is a link between vaccines and autism.

The 6-2 decision comes in the case of Hannah Bruesewitz, a 19-year-old Pennsylvania girl whose parents sued drug maker Wyeth claiming that a diphtheria, tetanus and pertussis vaccine led the girl to develop a seizure disorder and developmental delay.

Under a 1986 law, Congress established a special court to consider vaccine related claims and award compensation, as appropriate, from a fund which pharmaceutical companies contribute to. But the Bruesewitz case questioned whether the law prevented litigation against drug makers when a design defect was alleged.

In ruling this week, the Supreme Court affirmed that the law shields drug manufactures from lawsuits.

Though Bruesewitz does not have autism, the case was closely watched by parents who believe that the developmental disorder is related to vaccines.

Numerous scientific studies have determined that there is no link between autism and vaccines, yet thousands of families have brought claims to the contrary before the federal vaccine court in recent years.