The condition of U.S. Secretary of State John Kerry's wife, who is hospitalized in Boston, has been upgraded to fair.

The 74-year-old Teresa Heinz Kerry had been flown to Massachusetts General Hospital on Sunday after first being taken to by ambulance to a hospital on Nantucket, where the couple has a home. She was originally listed in critical but stable condition.

Glen Johnson, a spokesman for her husband, says doctors upgraded Heinz Kerry's condition after she underwent further evaluation.

A person in close contact with the family, who spoke on condition of anonymity because the person was not authorized to speak publicly about Heinz Kerry's condition, says she showed symptoms consistent with a seizure.

Johnson says her husband and other family members are with her at the hospital.