CEC-UW defined a “COVID case” as any patient seen in any of the 21 selected health systems from February 1 to December 31, 2020, who met at least one of the following three criteria:
- A positive COVID-19 PCR test and/or
- An ICD-10 diagnostic code for COVID and/or
- A positive COVID-19 antibody test
These included inpatients, outpatients, emergency admissions, and telehealth visits.