COVID-19 data: what does it tell us?

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In late April, Skagit County opened the drive-through COVID-19 testing at Skagit Valley College. By most measures, it has been a huge success. Just this week, the site broke a record and tested 599 people in one day! Widespread testing is critical to being able to slow the spread of COVID-19 and keep the community safe while businesses reopen. We’re so proud of our testing site team for all they have accomplished.

Testing also gives us real-time data on where COVID-19 is spreading and increasing in our communities, but as much as we’d like the data to be crystal clear and perfectly accurate all the time, it’s not. Because of this, there has been some confusion in the community about what our epidemiological data means. We want to clear it up.

Each day, Skagit County reports the following data points:

  • New cases: These are new, laboratory-confirmed cases of COVID-19. New positive cases are not recorded based on symptoms only. Positive cases must be confirmed by testing to be counted. Further, no matter how many times an individual is tested, a person can only be one positive case. Duplications are removed by the Washington State Department of Health and Skagit County Public Health. 
  • Recoveries: Our Public Health Department checks in with confirmed COVID-19 cases daily. After 21 days, a person is considered recovered if they also report that they are no longer experiencing COVID-19 symptoms. COVID-19 behaves differently in different people, and there have been some who have experienced symptoms for weeks or months, so it’s important to us that we only report recoveries for people who have actually recovered.
  • Hospitalizations: This is the total number of positive COVID-19 cases who were hospitalized at any point during their illness. It is a cumulative number, not the number of current people in the hospital.
  • Deaths: This is the number of Skagit County residents who unfortunately lost their lives due to COVID-19. As we get further into the pandemic—and are able to look back at the data more closely—it is possible that this number could change. This is because the Washington State Department of Health has been recording deaths of anyone who was a positive COVID-19 case and died. It’s possible that a person who passed away was a positive COVID-19 case, but they did not actually pass away from COVID-19. As we refine the data, you may see some deaths removed from the total because of this. We want to ensure that we report accurate data. Please understand that our reporting may change as time passes and we are better able to analyze and understand that data.

Public Health also talks regularly about the “rate of transmission,” or how many new cases Skagit County seeing per day. It’s important to remember that the rate of transmission both predicts the number of cases that will be coming in the next 14 days or so, and reflects the actions/precautions taken by the public in the last 14 days or so. For example, the rate of transmission from the Fourth of July—when we suspect a large number of people gathered together with people from outside their household—will not be apparent until this week. In many cases, COVID-19 has such a long incubation period that people who contracted COVID-19 two weeks ago may just now be developing symptoms and getting tested.

One final note: Data is not an exact science. For our Public Health team and the Washington State Department of Health to be collecting and releasing this data in real time is almost unprecedented, particularly with death data, which typically goes through a much more rigorous investigative process before they are considered final. We expect to make adjustments to case and death data as we continue battling COVID-19. But we promise that we’ll always give you the best data we have at the time.