California officials are urging COVID-19 vaccine providers to give booster shots to pretty much any adult who wants one.

It’s a messaging shift toward a looser interpretation of federal guidance, which appears to recommend boosters only for those 65 and older, in poor health or who live or work in a high-risk setting. Alarmed by the latest case rates, state health officials don’t want to be restrictive.

“Do not turn a patient away who is requesting a booster” who’s at least 18 years old and last had the Pfizer or Moderna shot 6 months ago or the Johnson & Johnson shot 2 months ago, California Public Health Director Dr. Tomás J. Aragón said in a memo this week to local health jurisdictions and providers.

The memo with the subject line “Booster Messaging,” Aragón said, “clarifies the state’s expectations for administering COVID-19 vaccine boosters and patient eligibility” and says providers should “allow patients to self-determine their risk of exposure.”

Santa Clara County health officials announced they would provide boosters to any adult on Wednesday.

It’s not clear that anyone who wanted a booster — regardless of their age or health status — has been turned away even before this latest message.

But Santa Clara County Health Officer Dr. Sara Cody said that the federal rules are “quite complicated” and likely are discouraging people from getting booster shots.

It wasn’t clear Thursday how quickly other Bay Area counties are adopting the new anyone-who-wants-a-shot-gets-one message.

Local health jurisdictions — including health officials in Alameda, Contra Costa, San Mateo and Marin — indicated this week they were adhering to the eligibility guidance from the U.S. Centers for Disease Control and Prevention and the state’s posted recommendations that, unlike Aragón’s memo, largely mirror them.

And some Bay Area health care providers, such as Sutter Health, and pharmacies such as Walgreens and CVS said Thursday they also are following the CDC’s eligibility guidance and limiting boosters.

The pharmacies’ online vaccine appointment schedulers ask those seeking boosters to attest that they meet the CDC’s guidelines but leave it up to the applicant to determine their eligibility — those below the recommended ages aren’t asked to submit verification of high-risk employment or health conditions.

Likewise, San Mateo County health department spokesman Preston Merchant said, “We’re saying to follow CDC guidance for eligibility, which includes self attestation and perception of risk,” suggesting those who consider themselves eligible won’t have trouble getting boosters.

California Health and Human Services Secretary Mark Ghaly on Wednesday hinted at the new “Booster Messaging” during a news conference in Los Angeles, stressing there is vaccine supply available, and the state is concerned about rising hospitalizations heading into the holiday season

“If you think you will benefit from getting a booster shot, I encourage you to go out and get it,” Ghaly said Wednesday.

The state defines high-risk jobs to include health care workers, firefighters, police, congregate care staff, teachers, school support staff, daycare workers, food and agriculture workers, manufacturing workers, correctional officers, public transit workers, postal workers and grocery workers. That guidance remained unchanged on the agency’s website Thursday.

Only 20% of Santa Clara County residents who are 6 months past their last Pfizer or Moderna shots or 2 months past their last Johnson & Johnson shots have gotten boosters, Cody said.

CDC data show only about one in three Californians 65 or older have gotten a booster vaccine, similar to figures in Texas, Florida and many other states. Among all adults 18 and older, the figures drop to 14%.

Cody and state health officials cited concerns that the state may be heading into another rise in COVID-19 cases this winter, with numbers once again trending upward.

President Biden in August announced plans for all vaccinated Americans to get boosters starting in September once they are eight months past their initial doses.

The booster campaign has been controversial from the start, with many health experts across the country arguing that it would distract from the far more important goal of getting shots into the unvaccinated and further fuel skepticism about the vaccines’ effectiveness.

Expert advisers to the CDC and the Food and Drug Administration recommended the shots only for older, chronically ill or otherwise high-risk people who originally had the Pfizer or Moderna shots, positions the agencies for the most part adopted. The advisers agreed that Johnson & Johnson vaccine recipients should get a second shot after two months because of evidence of waning immunity.

Pfizer this week asked the FDA to amend its booster authorization to include all adults, citing results of a new clinical trial that shows it’s safe and effective. Those results have yet to be peer reviewed or published.

A number of national health experts such as Eric Feigl-Ding, an epidemiologist and senior fellow at the Federation of American Scientists in Washington, D.C., and Ali H. Mokdad, professor of health metrics sciences at the University of Washington, have argued that the extra shots should be seen as part of the primary vaccination. Mokdad noted Thursday on Twitter that the measles vaccine is given in two doses and the diphtheria, tetanus and pertussis vaccine in three shots.

“We have a novel virus,” Mokdad tweeted, “and the science is telling us we need 3 doses to be protected.”