One of the hotbeds is Marin County, where officials are grappling with more than 1,400 cases among prisoners in San Quentin and a rapid spread in the Latino community, as essential workers in construction, food service, grocery stores or custodial jobs contract the virus and bring it home to their families.

On Friday, the state added Marin to a growing watch list of 21 counties where cases or hospitalizations are escalating.

The Bay Area confirmed 27,804 cases on Friday afternoon, with a death toll of 595.

Matt Willis, the public health officer for Marin County, helped set up an incident command center at San Quentin on Friday afternoon.

The county has received some help from philanthropic groups such as the Marin Community Foundation, Willis said.