https://www.mercurynews.com/2021/07/16/bay-area-health-officers-order-masks-indoors-for-all/

Amid a sharp rise in COVID-19 cases among the unvaccinated, eight Bay Area health officers made a united stand Friday and urged everyone to wear face masks while in public places indoors regardless of whether they’ve gotten their shots, walking back some face-covering freedom granted to the inoculated just a month ago.

With increased circulation of the highly transmissible Delta virus variant, Alameda, Contra Costa, Marin, San Francisco, San Mateo, Santa Clara, Sonoma and the city of Berkeley made the recommendation to ensure easy verification that all unvaccinated people are wearing masks and as an extra precaution for all.