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UPDATE: This story was updated Sept. 24 to reflect the CDC and state health department’s latest recommendations.

SAN DIEGO — California residents might be confused by a flurry of back-and-forth updates on third vaccine doses and COVID-19 booster shots: namely, who can get them and when?

While health regulators recently backed boosters of the Pfizer vaccine to targeted groups — and earlier approved a third shot for some higher-risk individuals — the path toward wide availability of extra doses (and the rules on who can get one now) remain a bit unclear.

Here’s the current state of play in the Golden State:

Booster shots: Now available (but only for some)

After a back-and-forth few weeks, the Centers for Disease Control and Prevention has recommended boosters of the Pfizer vaccine for the following groups at least six months after they complete their first two shots:

The CDC also said that the following groups may get a booster after the same time period (but notably, health officials soften their language from “should” get the shot to “may”):

  • people 18 to 49 years old with underlying medical conditions listed on their website
  • people 18 to 64 years old who are at increased risk for COVID-19 exposure and transmission because of occupational or institutional setting
    • This category is fairly open-ended, but the CDC listed the following examples: health care workers, teachers and day care staff, grocery workers and those in homeless shelters or prisons.

What if you are in the groups described above, but got the Moderna or J&J shot, not Pfizer? You’ll simply need to wait for trials on those vaccines and further recommendations from health regulators. Right now, advisors say you should not mix and match shots or schedule a third dose of your vaccine brand as a self-appointed “booster.”

Finding your booster appointment (it can be tricky)

California said Thursday that it will be ready on “day one” of federal approval to start administering booster shots, and people looking for appointments can head to the My Turn platform.

It’s already been adjusted to add a booster eligibility screener that helps people confirm they are among the millions of Americans who can now get one. You’ll be asked to verify your age and eligibility criteria and that you’ve already received the first and second Pfizer shot before being offered local appointments.

NOTE: It’s probably best to call individual locations and check ahead if you’re scheduling a booster during the initial rollout. While the CDC has approved the shots, not all local health providers may be ready or willing to provide boosters right away.

Sharp HealthCare, which popped up in a search for San Diego-area booster shots on My Turn Friday morning, told FOX 5 that they were not yet offering boosters, despite them turning up in the search. Meanwhile, Walgreens and some other local pharmacies found on My Turn said they were already offering them.

Some county-level leaders said Friday morning that they were still waiting on word from a western state safety review group before opening up booster shot supply — then that approval came just a few hours later, and state health officials encouraged eligible recipients to get their shots.

While there may be some confusion around the exact time that shots will be available from a given source, the California Department of Public Health does not believe supply will be an issue. “California is fortunate to have enough supply of Pfizer-BioNTech vaccine and is ready to get doses to the providers that need them,” a statement from CDPH reads.

The state also says doses will remain free regardless of health insurance or immigration status.

Third doses for the immunocompromised

State (and federal) health officials distinguish between “third doses” and “booster shots” when discussing extra vaccination eligibility, and the initial group that was able to make appointments for third shots included those who are “moderately to severely immunocompromised.”

For this group, third doses to strengthen immune response are available of both the Pfizer and Moderna vaccines (experts are still studying the potential for an additional dose of the Johnson & Johnson shot). It includes people who have:

  • Been receiving active cancer treatment for tumors or cancers of the blood
  • Received an organ transplant and are taking medicine to suppress the immune system
  • Received a stem cell transplant within the last 2 years or are taking medicine to suppress the immune system
  • Moderate or severe primary immunodeficiency (such as DiGeorge syndrome, Wiskott-Aldrich syndrome)
  • Advanced or untreated HIV infection
  • Active treatment with high-dose corticosteroids or other drugs that may suppress your immune response

Not sure if a third dose is right for you? Talk to your primary care provider before booking.

For help making a third dose appointment, Californians can go to the state’s My Turn CA dashboard, where they’ll be asked to verify that they have one of the listed conditions and that they received their second COVID-19 vaccine at least 28 days prior.

They’ll also be asked to verify which vaccine they have already received (current medical guidance says not to mix and match doses) and will have the option to request transportation assistance. Then the state will present local options for a third dose, including pharmacies and health care providers.

But what about that speech on boosters for all Americans?

You might remember a public address by President Joe Biden from August, in which his administration laid out plans to make booster shots widely available to nearly all Americans and targeted Sept. 20 as the start date.

“The plan is for every adult to get a booster shot eight months after you got your second shot,” Biden said at the time. “The time to lay out a plan for a widespread booster shot is now,” Surgeon General Dr. Vivek Murthy added.

Amid the fanfare of Biden’s speech, his administration did include the caveat that his booster plan hinged on recommendations and authorizations by federal health regulators. That was expected to come swiftly, but as of late September, debate is still swirling over some of the basic rationale for widely providing boosters.

Some top doctors question whether the plan will actually help slow the course of the pandemic more than a targeted approach to vulnerable groups only, and others say that more time to research the boosters’ effects are needed. Proponents argue that with the delta variant circulating the U.S. and driving back up case numbers, a booster shot will help strengthen protection and keep more high-risk people out of the hospital.

Meanwhile, the World Health Organization has strongly opposed the use of a third round of shots in wealthy nations while poorer countries don’t have enough vaccines to distribute first doses.

As an example of the topsy-turvy process of scientific debate, the FDA initially recommended booster eligibility for workers based on occupational settings, but the CDC’s top advisory panel left that consideration out of their recommendations — only to have the CDC’s director add that consideration back in when setting the final policy.

If your head is spinning, you’re not the only one, but medical experts point out that this is the kind of rigorous debate and consideration that goes in to making important recommendations. It’s just playing out with the added pressure of a president’s bold speech and an American public weary from the pandemic.

For now, stay tuned to the ongoing deliberations of the FDA and the CDC, and check back with this article for updates.

The Associated Press contributed to this report.