NAPA (CBS SF) — Following the lead of several other San Francisco Bay Area counties, Napa health officials issued an order Thursday, mandating indoor masking, regardless of vaccination status, in all workplaces and indoor public settings.

The county-wide order will go into effect at 12:01 a.m. Friday. Solano County is now the only Bay Area county without a face covering mandate.

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The decision, health officials said, was influenced by the recent significant increase in COVID-19 hospitalizations and ICU admissions in county hospitals due primarily to the Delta variant.

“The decision to go forward with a masking mandate, when Napa County has mostly followed state guidance, is based on the need to protect our healthcare system. Although Napa County has high vaccination rates, with 75% of eligible residents fully vaccinated against COVID-19, there is still a concerning rise in hospitalizations that is threatening hospital capacity,” said Dr. Karen Relucio, Public Health Officer for Napa County, in a news release.

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Even with the mandate, Relucio strongly believes that schools can and should reopen in full for in-person classes for all grades.

The Delta variant currently makes up 85% of the variants circulating in California and emerging evidence indicates that it is more transmissible, may cause more severe illness and that even fully vaccinated individuals can spread the virus to others.

A continued increase in the proportion of the population vaccinated is the best protection available, health officials said, but universal indoor use of face coverings is the least disruptive and most immediately impactful additional measure to take.

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“Masking is an essential tool that limits the transmission of the Delta variant as we continue to all get vaccinated,” Relucio said.