CEC-UW defines a “COVID case” as any patient seen in any of the 21 selected health systems from February 1 to December 31, 2021, who meet at least one of the following three criteria:
- A positive COVID PCR test and/or
- An ICD-10 diagnostic code for COVID and/or
- A positive COVID antibody test
The cohort includes all healthcare system patients, including inpatients, outpatients, emergency care, urgent care, telehealth visits, and COVID testing sites.