The massive bay doors of the San Mateo County Event Center stood wide open this weekend as thousands of eligible Dignity Health patients waited their turn to get their Pfizer shot. Volunteers ushered cars along the production line, waving large orange flags like aircraft marshals. It was the second of the countyâs mass vaccination clinics so far, and, by the end of the day Tuesday, around 4,300 San Mateo County residents would receive the first dose of their COVID-19 vaccine. The three-day clinic united Dignity Healthâs Sequoia Hospital, which provided vaccines and vaccinators, with a laundry list of county departments that offered the space and coordinated the logistics and safety of the site. County Health Information Officer Preston Merchant said the clinic will serve as a model for future partnerships with local health care providers or a blueprint for hospital systems to set up their own similar sites.