Case updates: COVID-19 transmission rate could be rising in King County

Confirmed cases by county
Department of Health

After dropping throughout March and into early April, the transmission rate of COVID-19 is no longer falling and could be rising again in western Washington, according to the latest report from Bellevue-based Institute for Disease Modeling (IDM).

A previous report issued last week found that the effective reproductive number—the number of new cases stemming from each COVID-19 infection—had dropped below the critical threshold of 1.0 in King County between March 29 and April 15.

However, updated case and mortality data from the Washington Disease Reporting System revised that estimate upward, showing the reproductive number had no longer been falling and likely has been inching up again since roughly April 6.

Because most of the population remains susceptible across the state, relaxing distancing policies will likely result in increased transmission.

However, researchers’ ability to measure these increases are retrospective, delayed by weeks because of the time until symptom onset and delays in case reporting.

“This report once again reminds us that our position is precarious and COVID-19 transmission and new cases remain unacceptably high,” said Dr. Jeff Duchin, Health Officer for Public Health – Seattle and King County. 

“We need to double down on distancing and other prevention steps at home, in the community, and in workplaces and we must see these numbers improve before relaxing our current restrictions.”

“It’s clear that the course of the epidemic in Washington remains sensitive to changes in social distancing,” said Dr. Mike Famulare, Principal Research Scientist at IDM. “We all—scientists, policymakers, everyone in Washington—face a difficult challenge in the coming weeks as our day-to-day lives will be in flux as we are forced to respond quickly to slow transmission and save lives.”

Case updates

46 people are currently staying in King County isolation, quarantine and recovery facilities, including Shoreline.

United States

• 1,248,080 known cases
• 75.477 deaths

State of Washington

• 16,388 known cases - up 157
• 905 deaths

King county

• 6940 known cases
• 485 deaths

Shoreline

• 316 known cases
• 49 deaths

Lake Forest Park

• 29 known cases
• 1 death