Counties across California likely will be allowed to ease restrictions on businesses and activities more quickly in the coming weeks as part of an accelerated reopening strategy state officials announced in tandem with a new policy targeting vaccine supplies to hard-hit communities.

In the Bay Area, the change could mean Contra Costa County will join Alameda, Santa Cruz and Solano counties in leaving the most-restrictive stage of the state’s coronavirus regulations as soon as next week.

And other Bay Area counties that have already graduated out of the “purple” tier, as the tightest limits are known, could in the near future have a quicker path to adopting even less-restrictive rules.

State officials late Wednesday announced a new strategy of reserving 40% of COVID-19 vaccine doses for less-wealthy neighborhoods that have borne a disproportionate share of coronavirus cases and deaths.

As those shots are delivered, they plan to relax standards for moving through the color-coded system that regulates activities such as indoor dining, youth sports and the size of gatherings in each of California’s 58 counties — though they stressed that the state will still have some of the tightest COVID-19 restrictions in the country.

“As we achieve higher levels of vaccine in our hardest-hit communities, we feel more confident that more activities can occur,” Health and Human Services Secretary Mark Ghaly said on a briefing call with reporters Thursday. But, he added, “We will keep our foot on the brake, not on the gas.”

Dr. Arthur Reingold, division head of epidemiology and biostatistics at UC Berkeley, said the strategy is “probably fair and reasonable.”

“But I would also say we have to wait and see how things go,” Reingold added.

The new standards would allow counties to move out of the purple tier and into the less-restrictive red tier — which allows for indoor activities at restaurants, gyms and other establishments — if they record an adjusted case rate of less than 10 cases per 100,000 residents per day for two straight weeks. The current threshold is 7 cases; state data showed Contra Costa County had a case rate of 9.5 this week.

The state will adopt the more generous standard once it has distributed 2 million doses of COVID-19 vaccines to residents of census tracts that rank in the bottom quarter of a health equity metric known as the California Healthy Places Index. The index grades census tracts based on income, education levels, health care access and other factors.

About 8 million people statewide live in the census tracts, which are spread across about 400 ZIP codes and include much of East San Jose, East and West Oakland and parts of Richmond, Gilroy, Antioch and Pittsburg. They also include wide swaths of the Central Valley and less-wealthy areas in Southern California.

As of Thursday, Ghaly said the state already has distributed about 1.6 million doses and estimated it will hit the 2 million mark “sometime in the next week or two.”

If that happens on Tuesday or later, and Contra Costa County’s case rate remains below 10, the county would advance into the red tier automatically. Without the new rules, the county would have to get its case rate below 7 for two straight weeks to move forward. A spokesman said the county is reviewing the new criteria.

The strategy likely will have a far bigger impact in Southern California and the Central Valley, where the tightest limits remain in effect for nearly every county.

The looser standards probably won’t immediately affect Alameda, Santa Cruz and Solano counties, which already are on pace to enter the red tier next week. Same with Santa Clara, San Mateo, San Francisco and Marin counties, which have all entered that stage over the past two weeks.

But the new rules could affect those counties in the near future: Once the state distributes another 2 million doses to the residents of those poorer, at-risk communities, for a total of 4 million, Ghaly said officials would further loosen the guidelines for entering the orange and yellow stages, which allow many more activities.

Under the orange tier, small amusement parks can reopen, along with outdoor bars, breweries and wineries that don’t provide food service, and indoor “family entertainment centers” such as bowling alleys.

Ghaly did not say precisely how the criteria for those two tiers would change or how long it could take for the state to distribute the additional 2 million doses. Gov. Gavin Newsom said Tuesday that California expects to receive a total of about 1.6 million doses next week, though some is earmarked for teachers and school staff. Supplies are expected to increase over the coming weeks and months.

The move to ease California’s standards is a far cry from states such as Texas that have dropped restrictions altogether, said University of California, San Francisco, epidemiologist Dr. George Rutherford.

“Prudence is their middle name in the governor’s office and the secretary’s office,” Rutherford said.