In this Jan. 24, 2021, file photo, Jenny Park, right, a clinical pharmacist with Virginia Mason Franciscan Health, explains the two-shot dosing of the Pfizer COVID-19 vaccine during a one-day vaccination clinic set up in an Amazon.com facility in Seattle. Monday, Oct. 18, 2021, was the final day for thousands of workers in Washington to prove they've been fully vaccinated for COVID-19 in order to keep their jobs. (AP Photo/Ted S. Warren, File)

October 18, 2021