Last night the US got its first dose of really bad coronavirus news, when Washington State announced it was the site of the country’s first coronavirus death on Saturday, while additionally reporting that two confirmed cases of covid-2019 were confirmed at a long-term care facility in Kirkland, Washington, prompting the state to declare a state of emergency, even as President Trump issued new foreign travel warnings and restrictions on Saturday afternoon in an effort to stop the spread of the virus, while also urging calm among members of the public.

There was worse news: researchers who studied two cases in the state say that the virus may have been spreading there for weeks, suggesting the possibility that up to 1,500 people in the state may have been infected. Specifically, the researchers compared two cases to learn more about how the coronavirus spreads. The viral mutations suggest that it has been spreading in the state for close to six weeks, according to one of the scientists who compared the sequences, Trevor Bedford, an associate professor at the University of Washington.

If that is true, it could mean that 150 to 1,500 people “have either been infected and recovered or currently are infected now,” said Mike Famulare, a researcher at the Institute for Disease Modeling in Bellevue, Wash., who performed the analysis. Those cases, if they exist, have thus far been undetected.

And most problematic of all, many of those people might not yet have symptoms even if they are contagious. Dr, Famulare characterized his estimate of community cases as a “best guess, with broad uncertainty.” Another method, based on census data and estimated sampling, produced similar results, he said.

This case, WA2, is on a branch in the evolutionary tree that descends directly from WA1, the first reported case in the USA sampled Jan 19, also from Snohomish County, viewable here: https://t.co/gxyo0PsJ7x 2/9 pic.twitter.com/LBH26A0AFC — Trevor Bedford (@trvrb) March 1, 2020

It's possible that this genetic similarity is a coincidence and these are separate introductions. However, I believe this is highly unlikely. The WA1 case had a variant at site 18060. This variant is only present in 2/59 viruses from China. 4/9 pic.twitter.com/Rb9N5uvgwg — Trevor Bedford (@trvrb) March 1, 2020

I believe we're facing an already substantial outbreak in Washington State that was not detected until now due to narrow case definition requiring direct travel to China. 6/9 — Trevor Bedford (@trvrb) March 1, 2020

We're hoping to update soon with better estimates of the number of infections in Washington State using available data. 8/9 — Trevor Bedford (@trvrb) March 1, 2020

An update, because I see people overly speculating on total outbreak size. Our best current expectation is a few hundred current infections. Expect more analyses tomorrow. — Trevor Bedford (@trvrb) March 1, 2020

Through Sunday, there were only 71 confirmed cases in the United States, although that is mostly a function of testing limitations; over the weekend the Food and Drug Administration announced that testing for the coronavirus would be greatly expanded in the country, a move that is expected to improve the pace of detecting infections and help identify patterns of suspected or confirmed cases. It may also result in hundreds if not thousands of new confirmed cases, and has already prompted a furious hoarding of provisions in what may be a harbinger of the panicked response that could descend upon the nation once the CDC admits there are thousands of domestic cases.