https://www.siliconvalley.com/2021/12/29/bay-area-counties-reverse-easing-of-coronavirus-mask-mandates-will-require-masks-indoors/

As COVID-19 cases and hospitalization rates rise again, Bay Area counties are tightening up health rules to require everyone — vaccinated or not — to wear masks inside public settings at all times.

Contra Costa, Alameda, Marin, Sonoma and San Francisco counties and the city of Berkeley announced this week that beginning Thursday, people will have to wear masks inside gyms, churches, offices and other places that had been exempted from mask rules as long as everyone was vaccinated..