Today’s report on COVID-19 in King County | Thu Apr 30

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 29, there were 6,308 confirmed cases of COVID-19 in King County, 126 more than the previous day.  There have been 446 confirmed deaths in King County due to COVID-19, 7.1% of all confirmed cases.

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


The three graphs below chart new cases, total case count and the logarithmic trajectory of cases.

The first graph shows new cases (blue bars) and the 7-day average (red line).  Of the 126 new cases reported today, 87 were confirmed yesterday and the remaining 39 were confirmed in previous days but reported to Public Health in the last day, resulting in restatements of the totals for previous days.  The 7-day average peaked at 188 on April 1 and has been in decline since then, but the 7-day average has leveled off during the last several days.  The trailing 7-day average is 90 new cases per day.  Three days ago it was 86 new cases per day.  At that point Dr. Jeff Duchin, Health Officer for Public Health – Seattle & King County, said, “We still have way too many cases occurring each day. That means we’re vulnerable to a rebound that could potentially overwhelm our healthcare system if we prematurely ease up on our distancing steps.”

The second graph shows the total case count.  With 6,308 total cases as of 11:59 pm yesterday, the compound daily growth rate during the last 7 days has been 1.5%, less than the 2.0% rate during the prior 7 days, but not a lot less.  1.5% seems like a small number.  It is much lower than the 8.5% compound daily growth rate for the seven-day period ending on April 1.  But it’s important to keep in mind that this is a compound daily growth rate on a base of more than 6,000 cases.  If we start with today’s total of 6,308 cases, a 1.5% compound daily growth rate (1.520% to be precise) yields 96 new cases in a day, 702 new cases in a week, and 3,315 new cases in four weeks.  This is why Governor Inslee and public health officials continue to emphasize that the numbers need to be lower before social distancing restrictions can be lifted.

The third graph 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.

Will Daugherty welcomes your questions and comments.  His email is