A previously undetected measles infection was found by an autopsy to be the underlying cause of a Washington state woman's death this spring, marking the first known U.S. fatality from the disease in 12 years, public health officials said on Thursday.
The woman from Clallam County, in the northwestern corner of the state, was most likely exposed to measles at a medical facility during a recent outbreak in the area, the state Department of Health said in a statement posted on its website.
She was there at the same time as another person who turned out to have been contagious with the virus, but never developed some of the common symptoms of measles, such as a rash, so her infection was not discovered until after her death, the agency said.
The woman also had several other health conditions and was on medications that contributed to a suppressed immune system. The cause of her death was ruled by medical examiners to be from pneumonia due to measles, according to the Health Department.
It was not immediately clear whether the woman had been immunized against measles, though the agency noted that people with compromised immune systems often cannot be vaccinated.
Even when vaccinated, such individuals may lack a strong immune response when exposed to the disease, making them especially vulnerable to outbreaks.
The last confirmed measles death in the United States was reported in 2003, the agency said.