SAN FRANCISCO, Calif. (KRON) – Several Bay Area counties are making changes to COVID-19 response due to the recent surge in omicron cases.

California became the first state to record more than 5 million known coronavirus infections, according to the state dashboard Tuesday.

San Francisco County

San Francisco Mayor London Breed and Health Director Dr. Grant Colfax Wednesday announced temporarily tightening universal indoor masking requirements and aligning with the state’s requirement of boosters among workers in healthcare and high-risk settings.

From Thursday, December 30th through January 31st, everyone in San Francisco County must wear masks inside regardless of vaccination status. This applies to offices and gyms.

And beginning February 1st, health care workers and those who work in high-risk settings will be required to have a COVID-19 booster shot.

Additionally, indoor mega-events will require up-to-date vaccinations, including boosters, starting February 1, 2022.

“Our residents how shown time and time again that they understand the importance of protecting public health,” said Mayor London Breed.

“Thanks to our high vaccination rates we are in a much better place than last winter, but there is real danger out there for those who are unvaccinated. We will continue to focus on taking the steps necessary to deal with this latest surge of cases, while also keeping our businesses open and keeping our kids in school, which is so important for our young people and their families,” Breed said.

Alameda County

The city of Berkeley and Alameda County also took back face mask amendments on Wednesday that allowed fully vaccinated people to go unmasked in certain settings.

Beginning Thursday, December 30th, everyone, regardless of vaccination status, must mask in all indoor public settings.

“Omicron may be more transmissible, but we have the tools to prevent infection,” said Dr. Nicholas Moss, the Alameda County health officer. “Because even a mild infection in a vaccinated person may be passed on to someone who could become hospitalized, we must take every precaution this winter.”

The change does not impact face masking requirements for school and youth settings.

Alameda County did not give a timeline of when this mandate will be lifted.

The county said it will use mask metrics to determine when indoor masking will be lifted for everyone.

Marin County

Universal indoor masking will return to all indoor public spaces in Marin County starting December 30th, according to Marin County Public Health officials on Wednesday.

“When we see numbers like this, it’s time to respond,” said Dr. Matt Willis, Marin County Public Health Officer.

“The mask exemption for certain settings was a pre-Omicron policy.”

Contra Costa County

Contra Costa County health services announced on Tuesday new masking requirements in all public indoor places.

Before the health order was announced, speakers and performers who were fully vaccinated and groups less than 100 people who were vaccinated were allowed to take their masks off indoors.

Sonoma County

Sonoma County announced on Wednesday that they will be joining the other Bay Area counties in rescinding the face mask exemption for fully vaccinated people.

Regardless of vaccination status, everyone will be required to wear a mask in all indoor public settings. This includes workplaces, gyms, churches and other public settings.

The previous order will remain in effect until 12:01 a.m. on Thursday, Dec. 30.

“Increasingly, we are seeing the virus that causes COVID-19 spread among people who are fully vaccinated,” Dr. Mase said. “The vaccine works. It greatly reduces the chances you will become severely ill or die if you contract the virus, but it won’t stop you from infecting others. If they are immunocompromised or unvaccinated, they could require hospitalization and even die. Wearing a well-fitted mask indoors in public settings will help keep you and those around you safe by slowing the transmission of COVID-19.”

This new order aligns with the statewide mask mandate that will expire on Jan. 15.

Face coverings in Sonoma County have been required in most indoor public settings since August.