The City of Berkeley along with Alameda, San Francisco, Sonoma and Marin counties all announced the return of masks to indoor settings Wednesday.
"It's prudent right now for us to take this measure of safety, where we know we can protect people against infection," said Dr. Matt Willis, Marin County Public Health Officer.
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An exemption in several counties previously allowed people to take off their masks if they were vaccinated.
With counties rescinding that exemption, masks will now be required in public spaces, including gyms and fitness studios.
"At this point it's just ridiculous, this has been two years on and off," said Adam Kovacs, owner of Sonoma Fit in Novato.
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He worries the change will keep people from signing up for gym memberships January 1, a time when the fitness industry typically thrives.
"We need that strong quarter after two years of being impacted as we have been," said Kovacs.
"Masks are good. They lower the risk, but what really minimizes the risk is maintaining good health," he continued.
Marin County Public Health Officer Dr. Matt Willis understands the frustration, but says the change is necessary due to the rising case numbers.
"Our hope is that as was experienced in other places, the omicron surge goes up very quickly it may plateau quickly and then start coming down, at which point we would be equally responsive in terms of removing any barriers and any overly restrictive policies at that point," said Willis.
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Meantime, San Francisco announced booster requirements for workers in healthcare and high-risk settings by February 1. Also that operators and hosts of indoor mega-events of 1,000 people or more, will be required to verify proof of up-to-date vaccinations, which includes a booster received at least one week prior to an event for eligible patrons and staff, or a negative COVID test.
San Francisco will also follow the CDC's guidance that people who test positive for COVID-19 but are asymptomatic are recommended to isolate for 5 days instead of 10, with masking for an additional 5 days.
San Mateo and Santa Clara counties tell ABC7 News masks had already been required in public indoor settings and that they did not have the exemptions other counties are now rescinding.