Portland area’s 3 largest COVID-19 mass vaccination sites will close in June, due to slowing demand Updated May 11, 2021; Posted May 10, 2021 The COVID-19 mass vaccination site at the Oregon Convention Center will close June 19.Photo courtesy of Josh Andersen/OHSU Facebook Share UPDATE 2:20 P.M.: OHSU officials say they also will close their drive-thru mass vaccination sites at Portland International Airport and Hillsboro Stadium in June. The operators of three of the state’s largest COVID-19 mass vaccination sites announced Monday that they plan to close in June due to shrinking demand. The Oregon Convention Center inoculation site will shutter June 19, and the drive-thru sites at Portland International Airport’s Red Economy parking lot and Hillsboro Stadium will cease operations June 25.