COVID-19 transmission at a crossroads in Washington state going into fall

The Washington Department of Health released the latest statewide situation report on Sept. 25.

Submitted by the Washington Department of Health

The Washington Department of Health released the latest statewide situation report on Sept. 25. The report shows COVID-19 case counts continue to decrease overall in both eastern and western Washington, though some counties are experiencing plateaus or increases in disease activity.

The report can be read at https://covid.idmod.org/data/WA_Situation_Report_17_COVID-19_transmission_across_Washington_State.pdf.

Report findings

Washington can crush the curve heading into fall if we all make some small improvements to our current efforts to contain the virus. We’ve held the reproductive number (how many new people each COVID-19 patient will infect) close to one across the state since July. As of September 10, the best estimates of the reproductive number were 1.14 in western Washington and 0.92 in eastern Washington. The goal is a number well below one, which would mean COVID-19 transmission is declining.

The DOH continues to see significant differences in disease activity from county to county. Benton, Clark, Franklin, Pierce and Spokane counties are experiencing plateaus in their case counts. This is a concerning trend, since COVID-19 risk may increase going into the fall. In Spokane County, we’re seeing increases in case counts after September 10, which is particularly notable because data for that time period is not yet complete and we anticipate case counts will continue to rise as more test results are reported.

Washington is at a crossroads statewide as people begin to spend more time indoors and some schools move to hybrid or other in-person models. Even slight increases in transmission due to these changes, may result in exponential growth. However, if we collectively make small improvements to our behavior and environments, we could decrease transmission enough to allow further K-12 school reopening. To illustrate, the report includes projections for Pierce County if transmission continues at current levels and if transmission decreases to mid-August levels.

“As the weather gets colder and people spend more time indoors, we must all take precautions to reduce the risk of COVID-19,” said State Health Officer Dr. Kathy Lofy. “If you gather inside with people outside your household, it’s critical to keep the group as small as possible. Limit the length of time you spend together and the number of gatherings you have. Everyone should wear face coverings and stay at least six feet apart. Opening windows can also improve ventilation, even if it means wearing extra layers to stay warm.”

DOH partners with the Institute for Disease Modeling, Fred Hutchinson Cancer Research Center, University of Washington and the Microsoft AI for Health program to develop this weekly report. More COVID-19 data can be found on the DOH website, https://www.doh.wa.gov/Emergencies/COVID19, and in the state’s risk assessment dashboard, https://www.doh.wa.gov/Emergencies/Coronavirus.