Social Distancing Has Slowed Coronavirus In King County: Reports

KING COUNTY, WA — Public Health of Seattle & King County is touting two new reports that show how well social distancing is slowing the spread of the coronavirus in western Washington.

Both reports found that transmissions of the coronavirus have been on the decline since the end of March. However, Public Health says the studies also show that if all distancing measures were lifted now, there would be a large spike in new cases by the end of the month.

The two reports were created by the Institute for Disease Modeling (IDM) in Bellevue and the Great Seattle Coronavirus Assesment Network, or SCAN. SCAN works by testing volunteers for the virus to see where the virus is spreading, and the Institute for Disease Modeling has been tracking transmissions of the virus since late February to model how it spreads.

In particular public health is interest in three key findings from both reports:

Rate of transmission

IDM's model shows that the number of patients who spread the virus to others is dropping thanks to social distancing. In early March, each person who caught the virus spread it to an average of three other people. Now, each new coronavirus patient spreads it to .64 other people. Put another way, every three people who catch the virus will only infect two others.

An estimate of coronavirus cases that have not been confirmed

The Institute of Disease Modeling has also found that roughly 200 people out of every 10,000 King County Residents has been infected with the coronavirus. This means roughly 46,000 people have been infected. Public Health says that's about 10 times the number of confirmed cases, but many who are sick have not been tested and patients with the virus can be asymptomatic.

How the virus is spreading

Public Health says SCAN's research is providing better insight into how the virus is still spreading. By April 26, SCAN had reportedly tested 8,443 volunteers for the coronavirus. Among 5,194 who had coronavirus-like symptoms, just 67 tested positive. Of the remaining 3,249 volunteers who took the test but said they did not have coronavirus symptoms, just five tested positive for the virus. Public Health says this information brings them one step closer to understanding how many asymptomatic people are carrying the virus around without knowing it.

Public Health officials say both reports confirm that social distancing has worked to slow the spread of the coronavirus, but that the county cannot afford to become complacent just yet.

“Although transmission has slowed, most people in our area remain vulnerable to infection and there are still too many cases reported each day," says Health Officer Dr. Jeff Duchin. "We need a better understanding of how people are being infected in order to further reduce the number of COVID-19 illnesses. At this time, staying home and away from others remains our best weapon against COVID-19."

In the meantime, the testing continues. SCAN is still looking for more volunteers to take the coronavirus test. In particular they say they're hoping to test children and key demographic groups like Black, Hispanic, Latinx and Pacific Islanders to better get a grip on how the virus is affecting King County's minority communities. Volunteers can enroll to get tested at scanpublichealth.org. SCAN will mail nasal swab tests to volunteer's homes.