Researchers in Washington, where first death was reported, say virus may have gone undetected for weeks.

2nd person dies in Wash.; infections reported in 5 states

SEATTLE — The coronavirus may have been circulating for weeks undetected in Washington state, a preliminary finding that could mean hundreds of undiagnosed cases, researchers said Sunday after analyzing genetic samples from two people.

State and local authorities stepped up testing for the illness as the number of new cases grew nationwide, with new infections announced in California, Illinois, New York, Rhode Island and Washington state. Authorities in the Seattle area said two more people had been diagnosed with the COVID-19 virus, both men in their 60s who were in critical condition, and two health care workers in California were also diagnosed.

Health officials in Washington state said Sunday night that a second person had died from the coronavirus.

In a statement, Public Health-Seattle & King County said a man in his 70s died Saturday. On Friday, health officials said a man in his 50s died of coronavirus. Both had underlying health conditions, and were being treated at a hospital in Kirkland, Washington.

Washington state now has 12 confirmed cases

Health officials earlier said 50 more people in a nursing facility in Kirkland are sick and being tested for the virus. The first U.S. case was a Washington state man who had visited China, where the virus first emerged, but several recent cases in the U.S. have had no known connection to travelers.

The health care workers are employed at a Vacaville, California, hospital and had exposure to a patient treated there before being transferred to UC Davis Medical Center in Sacramento, the statement said. That patient was the first person in the U.S. discovered to have contracted the coronavirus with no known overseas travel.

Alameda County declared a state of emergency on Sunday.

Elsewhere, authorities announced a third case in Illinois and Rhode Island and New York’s first case.

The hospitalized patient in Rhode Island is a man in his 40s who had traveled to Italy in February. New York confirmed Sunday that a woman in her late 30s contracted the virus while traveling in Iran.

As the fallout continued, Vice President Mike Pence and Health and Human Services Secretary Alex Azar sought to reassure the American public that the federal government is working to make sure state and local authorities are able to test for the virus.

Both said during a round of TV talk show appearances Sunday that thousands more testing kits had been distributed to state and local officials, with thousands more to come.

“They should know we have the best public health system in the world looking out for them,” Azar said, adding that additional cases will be reported and the overall risk to Americans is low.

But researchers at the Fred Hutchinson Cancer Research Center and the University of Washington on Sunday said they had evidence the virus may have been circulating in the state for up to six weeks undetected — a finding that, if true, could mean hundreds of undiagnosed cases in the area. They posted their research online, but it was not published in a scientific journal or reviewed by other scientists.

Scientists not affiliated with the research pointed out that for many people — especially younger, healthier ones — the symptoms are not much worse than a flu or bad cold.

”The symptoms are pretty nonspecific and testing criteria has been pretty strict, so those combinations of factors means that it easily could have been circulating for a bit without us knowing,” said Justin Lessler, an associate professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health.

Dr. Adam Lauring of University of Michigan called the findings “high quality work.”

Pence, named by the president to oversee the government’s response, said more than 15,000 virus testing kits had been released over the weekend. And, the administration is working with a commercial provider to distribute 50,000 more, he said.

Azar said more than 3,600 people have been tested for coronavirus and the capability exists to test 75,000 people.

CAROLYN KASTER/AP Vice President Mike Pence, joined by President Donald Trump, pauses during a news conference about the coronavirus on Saturday at the White House.