Berkeley and Bay Area health officers are recommending that everyone — regardless of vaccination status — wear masks indoors in public spaces as COVID-19 cases increase due to the more contagious Delta variant.

Health officers from Berkeley, Alameda County, Contra Costa, Marin, San Francisco, San Mateo, Santa Clara and Sonoma counties released a joint statement with the recommendation on Friday afternoon. The agencies have acted in tandem during the COVID-19 pandemic to enforce mandates, and recommend rules to the entire region.

“The Delta variant is spreading quickly, and everyone should take action to protect themselves and others against this potentially deadly virus,” Dr. Lisa Hernandez, Berkeley health officer, said in a statement. “After vaccination, masking is the next most powerful tool we have to protect ourselves and each other during this latest wave of infections.”

Health officers emphasized that people who are fully vaccinated are well-protected against the Delta variant, but asking that everyone wear masks will “ensure easy verification” and prevent virus spread across all groups.

When the state economy reopened on June 15 and the mask mandate was lifted indoors for fully vaccinated residents, many local businesses adopted an honor system for their customers, meaning formal vaccination proof is not usually required to go maskless.

Masks are still required in many public settings, including buses and public transportation, hospitals, long-term care facilities, homeless shelters and indoor at K-12 schools, childcare and other youth settings. Berkeley, along with the state, lifted the outdoor mask mandate in early May, barring very crowded outdoor spaces.

Alameda County currently has 70% of its residents above the age of 12 vaccinated, with almost 83% of people having received at least one shot. However, cases have been increasing throughout the region since the reopening date, with the vast majority of cases among people who are not vaccinated. The Delta variant comprises almost 60% of cases throughout the country.

There have been 88,891 cases of COVID-19 (an increase of about 1,400 since Monday) recorded in Alameda County since the beginning of the pandemic, with 1,220 deaths. In Berkeley, there have been 3,752 cases (up 36 from Monday), and 50 deaths. The state and the county both have test positivity rates around 3.5%, which was 1.5% at the beginning of July.

Supriya Yelimeli is a housing and homelessness reporter for Berkeleyside and joined the staff in May 2020 after contributing reporting since 2018 as a freelance writer. Yelimeli grew up in Fremont and...