CDC recommends entire Bay Area issue indoor mask mandate

The Centers for Disease Control and Prevention (CDC) revised its masking guidance Tuesday to advise that all individuals — including vaccinated ones — wear masks indoors in areas with “high” and “substantial” COVID-19 transmission.

According to the CDC’s map, four Bay Area counties — San Francisco, Alameda, Contra Costa and Solano — are classified as areas of “high” transmission and the other five — Santa Clara, San Mateo, Marin, Sonoma, Napa — are classified as areas of “substantial” transmission. Masking is currently recommended but not required in every Bay Area county except Solano.

Given how Bay Area counties have previously handled the pandemic, it seems highly likely the region will turn their recommendations into mandates following the updated CDC guidance. A mask mandate is currently in effect in Los Angeles County.

Across California, most counties fall into the “high” or “substantial” categories.

California Gov. Gavin Newsom said Tuesday the state would issue updated statewide guidance sometime after the CDC guidance was released.

The CDC said the change in guidance is based on new evidence showing that while fully vaccinated individuals are protected against severe disease from the delta variant, they can transmit it to unvaccinated individuals more easily than other strains of the virus.

CDC Director Dr. Rochelle Walensky said that when earlier strains of the virus were dominant, infected vaccinated people were found to have low levels of virus in their nose and throats and were deemed unlikely to spread the virus. That has changed with the delta variant, where Walensky said the level of virus in infected vaccinated people is “indistinguishable” from the level of virus in infected unvaccinated people.

The Associated Press contributed to this report.