In a move criticized by business groups and hailed by labor advocates, California’s workplace regulators on Thursday extended the state’s coronavirus pandemic regulations into next year with revisions that employers said could worsen the state’s severe labor shortage.

The revised rules require that vaccinated but asymptomatic workers who come in close contact with someone infected with the virus must wear masks and stay 6 feet (1.8 meters) from others for 14 days if they return to work.

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The current rules allow those employees to keep working without restrictions unless they show symptoms — under the assumption that the vaccine generally will protect them.

An unvaccinated worker who comes in close contact with someone infected with the virus still must quarantine for two weeks.

The new rules that take effect Jan. 14 for three months in the most populous state were approved by the California Occupational Safety and Health Standards Board. The seven-member safety board is the policy-making arm of what is known as Cal/OSHA. It adopted the revised rules without discussion on a 6-1 vote.

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Business groups argued the new rules will be particularly onerous for small businesses including restaurants and retailers.

“Treating vaccinated and unvaccinated people similarly really denies the scientific value of the vaccine and disincentivizes vaccination,” said Rob Moutrie, a policy advocate for the California Chamber of Commerce.

But groups representing California workers supported the changes. Mitch Steiger, a legislative advocate for the California Labor Federation, said regulators last summer were foolish to loosen COVID-19 workplace restrictions put in place earlier during the pandemic.

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“It’s good that we’re realizing that vaccines aren’t the silver bullet to get us out of this,” Steiger said. “There’s never a good time to start disarming against COVID-19.”

The safety board’s adoption of the revised rules came a day after California reinstituted requiring vaccinated and unvaccinated people to wear masks indoors in a bid to slow the spread of the virus, including the omicron variant, as families and friends gather for the holidays and new coronavirus cases increase.

Safety board members recognized “the science that vaccinated people can transmit the virus, and early reports show that to be especially true with omicron,” said Saskia Kim, speaking for the California Nurses Association.

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Other states besides California that have adopted emergency COVID-19 workplace safety measures include Michigan, Oregon and Virginia.

The Biden Administration has ordered all U.S. employers with more than 100 workers to be vaccinated, tested regularly or wear masks at work starting Jan. 4. But the order is stalled amid court challenges from Republican-led states and fears among employers that the rules could make the worker shortage worse.

The California Chamber of Commerce led a coalition of about 60 business groups arguing in a letter to the state safety board that vaccinations are still largely effective and usually prevent serious illness and death even if there are breakthrough infections.

The groups warned that the new rules to require testing of vaccinated workers with no symptoms could strain the availability of rapid tests and boost employers’ costs. The rules apply to almost every workplace in the state, including offices, factories and retail locations.

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The stricter safeguards “will only worsen the present labor shortage affecting California workplaces,” Moutrie predicted. “Moreover, reinstituting social distancing on a per person basis is just not feasible in many work places” that would have to physically move workstations or equipment.

California has a huge entertainment business sector and Motion Picture Association of America vice president and senior counsel Melissa Patack told the board that the rules aren’t feasible for filming movies, television shows or commercials because “actors cannot wear masks while performing.”

She added that workers doing hair and makeup for actors cannot stay six feet (1.8 meters) apart, so the new rules “could result in the shutdown of many productions.”

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While California’s labor groups generally backed the workplace changes involving vaccinated and unvaccinated workers, they are upset that other proposed rules to be considered in March would eliminate mandatory employer-paid sick leave for workers who get infected with the virus or are exposed to it.

That temporary rule is aimed at allowing lower-wage workers without sick time to take time off rather than spreading the virus at work because they couldn’t afford to stay home.

Doing away with it would mean that “workers will be forced to make the impossible decision of going to work while sick or staying home without pay,” Stephen Knight, executive director of the labor advocacy group WorkSafe said in an online petition to the Cal/OSHA Standards Board.

Labor advocates could also work through the state budget process, Legislature and governor to keep the program, but prefer to retain the existing requirement, Knight and Steiger said.