Mass COVID-19 vaccination site opens at Clark County Event Center Updated Jan 26, 2021; Posted Jan 26, 2021 FILE — A CVS staff member prepares the Pfizer COVID-19 vaccine at Rose Villa Senior Living in Oak Grove, just outside of Portland, on December 21, 2020. Brooke Herbert/The Oregonian Facebook Share By Wyatt Stayner | The Columbian Clark County’s mass COVID-19 vaccination site opened at 9 a.m. Tuesday morning, but all available appointments at the site this week were taken by early Monday morning. The site, at the Clark County Event Center at the Fairgrounds, will be open from 9 a.m. to 5 p.m. Tuesdays through Fridays.