FOSTER CITY (KPIX) — As San Mateo County officials weighed increased restrictions in the face of rising COVID cases, one supervisor offered a blunt message to the unvaccinated.

Health officials with cities and counties across the bay area are grappling with whether to bring back mask mandates.

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In San Mateo County, you have had to wear a mask inside any city-operated building — like city hall in Foster City — since the mandate went into effect Monday. There currently is no mask mandate for restaurants, gyms or other businesses, but that could soon change.

“We’re going to sort of have to explore that. We’re driven by two pieces of evidence. What are they? In all these decisions: number of cases and hospitalizations,” said San Mateo County Supervisor David Canepa.

New guidelines from local and federal health officials have been a rollercoaster this past week.

California health officials on Wednesday aligned with the CDC’s latest indoor mask guidance, recommending all people wear face coverings in public indoor space where there high or substantial levels of transmission.

Some counties and cities have new recommendations, while others are instituting new mandates, leaving many residents confused.

“I always carry my mask,” said the supervisor. “So wherever you go, carry your mask.”

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Canepa says over the last two weeks, COVID cases have nearly doubled in San Mateo County. The rising number of cases spurred the county to begin requiring masks in all county buildings starting this week in hopes of protecting residents from the Delta variant and slowing it’s spread.

The latest numbers show almost 90 percent of those eligible in San Mateo County are fully vaccinated. For anyone who still has not received their shot, Canepa had a message.

“To those who are unvaccinated, shame on you! Shame on you!” the supervisor said. “We’re in a life and death situation and the decision that you’re making is affecting my residents. And you’re affecting residents who live in the state of California.”

Canepa says over the next several weeks, county health officials will be keeping a close eye on case numbers to see if increased or decreased restrictions are needed.

The county later tweeted that officials were not considering a mandate for masks or social distancing, but did recommend masking for all residents in public indoor spaces.