Today’s report on COVID-19 in King County | Sat Apr 18

This daily synthesis of the Public Health data is provided by Will Daugherty of Pacific Science Center.  Thanks Will!

Public Health has updated the data dashboard.  As of 11:59 pm yesterday, April 17, there were 5,063 confirmed cases of COVID-19 in King County, 161 more than the previous day.  There have been 340 confirmed deaths in King County due to COVID-19, 6.7% of all confirmed cases. 

The numbers that Public Health reports each day include delayed results from previous days.


The first graph below shows new cases (blue bars) and the 7-day average (red line).  Of the 161 new cases reported today, 85 were confirmed yesterday and the remaining 76 were confirmed in previous days but delayed in reporting.  We see a definite flattening of the curve with the 7-day average continuing to decline since April 1.  At the same time, the trailing 7-day average remains at 96 new cases per day, a long way from zero.

The second graph below shows the total case count.  With 5,063 total cases as of 11:59 pm yesterday, the compound daily growth rate during the last 7 days has been 2.1%, slightly more than half of the 3.9% rate during the prior 7 days.  At a 2.1% compound daily growth rate, the number of cases doubles every 34.0 days.  One week ago, cases were doubling every 18.2 days.  Two weeks ago, cases were doubling every 10.4 days. Three weeks ago, cases were doubling every 6.6 days.

The third graph below shows the trajectory of cases in King County with the total number of cases on the horizontal axis and the new cases on the vertical axis.  Each axis is on a logarithmic scale.  Each blue dot represents a daily report.  The dot farthest to the left is the February 28 report.  Time passes from left to right as the total case count grows.  The dot farthest to the right is today’s daily report.  We can see a clear change in the trajectory since March 28, shortly after Governor Inslee’s “Stay Home, Stay Healthy” order on March 23.  Here is a good video explaining the benefits of plotting the trajectory in this way (3:20 mark if you want to skip the intro).

Will Daugherty welcomes your questions and comments.  His email is

What else does Public Health want you to know today?

Otherwise, the Public Health Insider published an interview with Dr. Jeff Duchin, Health Officer for Public Health — Seattle & King County by ProPublica and The Seattle Times.  They discussed his and the department’s thinking related to the timing of Public Health recommendations to avoid and subsequently prohibit large public gatherings, and in particular in not prohibiting the Sounders match on March 7th. The overview of information Dr. Duchin shared in his conversation and through e-mail is available in the full article here.