WASHINGTON — Vaccine makers are protected from lawsuits, the Supreme Court ruled Tuesday, dashing the hopes of a US couple who had sought monetary damages after their daughter fell ill after a round of routine childhood inoculations.

By a 6-2 vote, the US high court, in an opinion by written Justice Antonin Scalia, rejected the family’s argument that they should allowed to sue drug maker Wyeth for not making a safer vaccine.

The case concerned Hannah Bruesewitz, who as a six-month-old infant received a series of injections to protect her against diphtheria, tetanus and pertussis, the illness also known as whooping cough.

The family, from the northeastern state of Pennsylvania, found that after the third injection, the cognitive development of their now-teenaged daughter slowed dramatically and she developed seizures and other health problems that continue to this day.

The family insists that the girl’s medical problems were a side-effect of the vaccine; Wyeth, the manufacturer, over the years has steadfastly denied any link exists between the girl’s condition and its vaccine.

The US high court ruled that the vaccine maker, which is owned by Pfizer Inc, the world’s largest pharmaceutical company, is not subject to the liability laws that govern some other products.

The court ruled […]