SEATTLE (BLOOMBERG) - Washington State officials are investigating a potential outbreak of coronavirus at a health facility that cares for elderly, vulnerable patients, after two people at the facility were infected.

Two people at a LifeCare nursing facility in Kirkland, Washington, were diagnosed with the virus, health officials there said on Saturday (Feb 29).

One is a health-care worker in her 40s, and is in satisfactory condition at a local hospital. The other is a female resident of the facility in her 70s, and is in serious condition at the same hospital, local health authorities said.

In addition, more than 50 residents and staff at the facility have shown symptoms of a respiratory illness, according to Jeff Duchin, health officer for public health in Seattle and King County.

Tests of the residents are ongoing.

"We are very concerned about an outbreak in a setting where there are many older people," Duchin said on a call with reporters on Saturday. "We're going to send a team into the facility tomorrow to do an assessment."

About half of the people with symptoms are residents, and half are staff.

Additional cases are expected from the facility, said the local and state health department in a statement.

Kirkland is located just outside Seattle.

The potential outbreak is the latest worrying sign that the coronavirus may be circulating more widely than previously known in some parts of the country.

Earlier on Saturday, Washington State reported the first US death from the virus, a man in his 50s with underlying health conditions.

Governor Jay Inslee has issued an emergency proclamation in Washington to coordinate the response to the coronavirus.

Health officials have said that that a lack of testing has probably meant that cases haven't been identified, or identified as early as they might have been otherwise.

"If we had the ability to test earlier, I'm sure we would have identified more patients earlier," Duchin said on the call with reporters.