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COVID-19 Incident Rate Explained

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September 02, 2020
Kittitas County, WA - 09/02/2020 - The COVID-19 Incident rate in Kittitas County continues to be a source of confusion, frustration and anger within the county. Because the incident rate is used to make recommendations on how schools should proceed, that specific piece of information is getting a lot of attention. The incident rate information will be explained here in hopes that people will have the information they need in order to feel up-to-date. In order to be informed about COVID-19 disease activity in Kittitas County, it is essential to understand the difference between active cases and the rate per 100,000. These are two very different pieces of information.

The incident rate is not the active case rate.  The active case rate is a daily number of how many people are positive with COVID-19 and isolated in Kittitas County.  Active cases can spike and drop each day (as we have seen), depending on what is happening in our county.  For example, just today, we added 5 new positive cases to our daily rate.  The active cases (people who are positive and isolated) can change drastically from day to day.
 
The incident rate is a two-week count of disease activity for COVID.  How do we get that number? We figure this number out by adding every single positive case in our county for a total of a two-week period.  That number of all positives for 14 days is divided by the number of our population (46,570 via the Office of Financial Management’s population estimation for 2019 for our county) and then multiplied by 100,000.  14 days of COVID-19 positives are calculated for the incident rate so it does not fluctuate quite as drastically as the daily active case count. 
 
We figure that the average citizen is trying to calculate the incident rate by starting to count back 14 days. We do not start the incident rate yesterday and go 14 days back.  If we did that, the numbers would be wrong.  Why?  Because we do not have all of the test results from that time period.  If someone got tested two days ago and they were positive, that wouldn’t get calculated in the incident rate.  We actually count back 10 days and then start the 14-day count for the incident rate.  We do this because we know with 90-percent certainty that we have all of the test results for that time period.
 
We continue to provide data with daily updates on the Kittitas County Community Impact Dashboard to notify the community of what COVID-19 looks like here.  To provide a “one stop shop” for information, we have also started listing the Washington State Department of Health’s incident rate on our local dashboard. 
 
If you have questions about your health, please contact your healthcare provider or you can call the Temporary COVID Clinic at KVH at 509-933-8850.  If you are having a medical emergency, call 911 or go to the Emergency Department at KVH.  If you have general questions about COVID-19, please call the EOC at 509-933-8315 or 509-933-8305.

 
Kittitas County, from the Cascades to the Columbia, and online at http://www.co.kittitas.wa.us
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For more information:
Kasey Knutson, Public Information Officer, (509) 962-7515
Contact:
Kasey Knuston
509-962-7515