By Craig Lazzeretti

Assistant managing editor

(Wednesday, Dec. 15) A new state order reinstating a mask mandate for indoor public settings will have no impact on Contra Costa County and Rossmoor, county health officials said.

That’s because Contra Costa was already requiring that masks be worn inside public facilities, with limited exceptions, when the new state order took effect Dec. 15. In a news release that day, Contra Costa Health Services said the limited exceptions will remain in effect during the state order, which is scheduled to last through Jan. 15, at which time state officials will provide further guidance as needed in response to the pandemic.

The exceptions apply to “controlled” spaces not open to the general public where all attendees show proof of full vaccination. No more than 100 people can be present, and the gathering has to consist of the same group that meets regularly.

That exception has allowed Rossmoor clubs and organizations to hold indoor activities without masks as long as they meet the county’s requirements.

“The limited exceptions we made are for very low-risk scenarios where everyone is vaccinated,” county Health Officer Dr. Chris Farnitano said in the county’s news release. “Our community already understands and is following these rules, and it would be confusing to change them for just one month.”

Unlike Contra Costa County, many counties in the state had lifted their own indoor mask mandates as case rates declined. But the California Department of Public Health chose to reinstate it for all counties in response to a 47% spike in COVID-19 case rates statewide since Thanksgiving and a 14% rise in hospitalizations.

In Contra Costa County, active COVID-19 cases were up 19% and hospitalizations were up 10% in the two-week period ending Dec. 14.

The state order also comes as concern grows about the new omicron variant. In an update to the Contra Costa County Board of Supervisors on Dec. 13, Farnitano said early data indicate omicron is likely two or three times as contagious as the delta variant, which continues to be by far the dominant strain in the county.

To make matters more concerning, there appears to be “very little if any protection from natural immunity from an infection with a prior strain” to omicron, Farnitano said, and current coronavirus vaccines appear to be less effective at preventing infection.

He strongly urged county residents who are fully vaccinated to get booster vaccine shots if they haven’t already.

“You really need to get boosted to get strong protection against omicron,” he said.

One bright spot is early evidence shows that omicron causes milder illness than previous COVID-19 strains. But, Farnitano warned, that advantage could be offset by its much higher transmission rate, potentially driving up hospitalizations even if a lower overall percentage of cases result in serious illness.

“We can’t just rest on the hope that omicron is milder,” he said.

The Department of Public Health took other steps last week to try to curb a winter COVID surge. Before attending a “mega event” such as a concert or sporting event, people will be required to provide either proof of vaccination, a negative antigen COVID-19 test within one day of the event or a negative PCR test within two days of the event.

Officials also issued a new travel advisory recommending that all travelers arriving in California test for COVID-19 within three to five days after arrival, regardless of their vaccination status.