Face Coverings Directive Begins & Today’s COVID-19 Report | Mon May 18

The directive to wear face coverings while in public goes into effect today, May 18, to help slow the spread of COVID-19. While facial coverings do not replace proper hygiene or physical distancing, a cloth face covering may help to protect others and slow community spread of COVID-19 by blocking infectious droplets from spreading when someone with the infection coughs, sneezes or speaks.

Wear a face covering when you are at any indoor or outdoor public space where you may be within 6 feet of someone who does not live with you.  Further details are all available in today’s update on the Public Health Insider.  They also published an article with tips on making DIY cloth masks for you crafters out there.

Otherwise, 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, May 17, there were 7,529 confirmed cases of COVID-19 in King County, 49 more than the previous day.  There have been 523 confirmed deaths in King County due to COVID-19, 6.9% 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 49 cases reported today, 30 were confirmed yesterday and the remaining 19 were confirmed in previous days.  The 7-day average of new cases per day peaked at 191 on April 1.  The average for the last 7 days is now 54 new cases per day, the lowest since March 13.

The second graph shows the total case count.  With 7,529 total cases as of 11:59 pm yesterday, the compound daily growth rate during the last 7 days has been 0.7%, slightly less than the 1.0% rate during the prior 7 days.  If we start with 7,529 cases, a 0.7% compound daily growth rate (0.741% to be precise) yields 56 new cases in a day, 399 new cases in a week, and 1,728 new cases in four weeks.  With 7,529 cases, the compound daily growth rate must be less than 0.133% in order for the number of new cases per day to be less than 10.

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.  The downward trajectory that began March 28 – April 1 (shortly after Governor Inslee’s “Stay Home, Stay Healthy” order on March 23) has accelerated in the last several days.

Will Daugherty welcomes your questions and comments.  His email is wdaugherty@pacsci.org