The number of coronavirus cases confirmed by the University of Washington Medicine Virology Lab peaked in late March and the daily positives have been dropping ever since, UW Medicine announced Friday.
However, in a separate press conference, Gov. Jay Inslee noted that there are signs that the rate of infection is on the rise.
In the analysis published Friday by researchers from the UW Virology lab and Fred Hutchison Cancer Research Center, researchers looked at positivity rates for specimens received from 10 counties and Seattle-area emergency departments. Patient samples were from March 1 to April 16.
The peak in positive results occurred around March 28-29, according to the analysis.
Researchers noted the peak and decline appear to align with social distancing measures taken by state and local authorities. The statewide ban on in-dining restaurants and gatherings was on March 16. The stay-home order started on March 23.
Researchers said changes in physical distancing practices and the reopening of businesses could change the trajectory of the spread.
In a separate press conference, Inslee in a press conference Friday worried about how the gradual lifting of restrictions in the state's stay-home order will affect the spread of coronavirus.
He data from COVID-19 projection models show that the rate of infection is increasing in Washington state and he urged people to follow his measured approach to slowly reopening the state from his stay-at-home restrictions.
The Democrat said data showed that the reproductive rate of the coronavirus in Western and Eastern Washington was above three when the outbreak was first detected in late February and March.
That means each infected person infects about three others.
It has since dropped to about one, but data up to April 19 shows that the reproduction rate is on the upswing.
State receiving more testing supplies
Inslee on Friday also said the state is making significant progress in getting collection materials to help test for the novel coronavirus, which causes the respiratory illness COVID-19.
He said the state has received its first shipment of 37,000 swabs of collection materials for testing from the federal government. The state is expected to get another 60,000 swabs next week.
After that, the governor said the state should get weekly shipments of the testing materials, which he said will be crucial as the state slowly continues reopening and the need for testing becomes greater.
Gov. Inslee also said he is in talks with the Federal Drug Administration to validate at-home testing kits.
According to the Washington state Department of Health, more than 16,000 people have tested positive for coronavirus, including nearly 900 people who have died. Statewide there have been more than 230,000 people tested, and there has been a 7% positive rate.