OES and the Federal Emergency Management Agency opened and jointly operated the site from mid-February as part of a federal effort to establish 100 large-scale vaccination sites across the country during President Joe Biden's first 100 days in office. Alameda and Contra Costa counties began jointly operating the site with the OES last month after it was announced that federal emergency personnel would be ending their work at the Coliseum. The two counties will complete scheduled appointments for second doses through May 23 in partnership with local health care entities like the Native American Health Center and Bay Area Community Health. After that, Chowla said the county plans to shift resources from the mass vaccination site toward communities that have been hardest hit by the pandemic and are still most at risk of developing new cases.