(CNN) — Some states are not waiting. At least five so far — ArkansasCaliforniaColoradoNew Mexico and West Virginia — have expanded eligibility for Covid-19 booster shots to everyone 18 and older, six months after their second dose, even though the US Food and Drug Administration hasn’t done so yet and the US Centers for Disease Control and Prevention hasn’t given its recommendation.

So far, the federal health agencies have only given the green light for Pfizer/BioNTech and Moderna boosters to be administered to adults ages 65 and older or any adults at high risk of severe Covid-19 or who live or work in long-term care settings or high-risk settings who completed their second dose at least six months ago. All adults who have received the Johnson & Johnson vaccine at least two months ago are eligible for boosters.

But that could soon change.

As the US waits for the FDA to authorize boosters for all adults, frustration has grown within some communities and among some public health experts who argue there is an urgent need to move quickly to get boosters into more arms.

For some states, “the reason they’ve gone ahead and done this is they are really concerned about experiencing another wave in their state of transmissions and we have seen in some states an uptick in Covid-19 cases. Unfortunately, a lot of those are driven by those who are not vaccinated, but there are some breakthrough infections among those who are vaccinated,” Hemi Tewarson, executive director of the National Academy for State Health Policy, told CNN on Tuesday.

“From a public perception, there are some that really do want the boosters. They are worried about breakthrough transmission,” Tewarson said. “So, I think this is where governors — at least some governors — are trying to address the tension here of some in the public who really want to take that extra step even though we don’t know yet what all the data tells us.”

‘Frustrated’ and waiting

Overall, some states have moved forward in deciding to expand eligibility for boosters, Tewarson said, adding that the move is similar to how early on in the pandemic some states required masks in public spaces even though there was no federal mask policy.

Most of the states that have expanded eligibility for booster doses to all adults have seen recent upticks in Covid-19 case numbers and hospitalizations — and state public health authorities have the “ultimate decision” on responding to such public health matters, Dr. Mark McClellan, director of the Duke-Margolis Center for Health Policy at Duke University and a former FDA commissioner, told CNN on Tuesday. Those increases in cases are occurring as the winter season approaches.

“I think that assessment of being under higher risk now is what’s driving some of those decisions,” McClellan said.

“But I do know that all the states are waiting for further guidance from the FDA and the CDC based on any new evidence that’s come in,” he said. “I would expect FDA to go ahead this time with authorizing boosters more broadly and then CDC confirming that and then you’ll see kind of all the states go further.”

In Colorado for instance, about 81% of people hospitalized for Covid-19 are unvaccinated but for the 19% who are vaccinated, booster doses can help bring their case numbers down, Governor Jared Polis told CBS’ Margaret Brennan on Face The Nation on Sunday.

“I’ve been very frustrated with the convoluted messaging out of the CDC and the FDA,” Polis told Brennan.

“Everybody should get the booster after six months. The data is incredibly clear that it increases your personal protection level — that’s why my parents got it, I got it, my family members got it,” Polis said. “But it also can help improve the epidemiological state of a particular state or of the entire country, because you have folks that are ready to roll up their sleeves and add that extra protection, to go from 70% or 80% protection back to that 90% to 95% level of protection, which can really have an impact in preventing the spread of the virus.”

His state announced last week that there is a “significant wave of disease spread” and about 1 in 48 Coloradans is estimated to be infectious.

FDA authorization could come any time

Pfizer and BioNTech were the first vaccine makers to request expansion of eligibility for their Covid-19 booster shot to all adults.

Last week, Pfizer and BioNTech asked the FDA to amend the emergency use authorization for their vaccine so that all adults are eligible for a booster shot. Currently, boosters are authorized for a more limited group of adults.

When such requests are made to change an emergency use authorization, typically the FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) will meet to discuss the request and make a recommendation about how the FDA should proceed.

But this time, the FDA does not plan to convene VRBPAC to discuss expanding eligibility for the Pfizer/BioNTech Covid-19 booster shots, FDA spokesperson Alison Hunt confirmed to CNN in an email Tuesday. The FDA concluded that Pfizer/BioNTech’s request does not raise questions that would require additional discussion by the advisory committee, which is made up of outside experts.

Without a committee meeting, the FDA’s authorization decision could come any time.

“While the FDA cannot predict how long its evaluation of the data and information will take, the agency will review the request as expeditiously as possible,” Hunt noted.

A separate panel of CDC vaccine advisers is scheduled to meet Friday to discuss expanding booster eligibility for Pfizer’s Covid-19 vaccine, CDC spokesperson Jason McDonald said Tuesday. CDC’s Advisory Committee on Immunization Practices typically meets only once a vaccine has been authorized by the FDA — a further sign that the FDA authorization could come any time this week.

Reviewing Pfizer’s request to authorize Covid-19 booster shots for all adults is “highest priority” for the FDA, the agency’s top vaccines official told CNN on Monday.

“At this time, the review of the expanded Booster request has highest priority at the Center for Biologics Evaluation at FDA,” Dr. Peter Marks, director of the FDA’S Center for Biologics Evaluation and Research, told CNN in an email.

“Although we can’t give an exact date for the completion of this process, we are working on reviewing the request and evaluating the data with all due speed given the current public health emergency,” Marks wrote.

“FDA is moving as rapidly as possible to address recently submitted information related to expanding the population of individuals eligible for boosters,” he added. “As is apparent from the previous public discussions of boosters, the thinking of experts in this area related to supporting boosters for all individuals over age 18 years has evolved very rapidly.”

Recent studies suggest that while vaccination still provides strong protection against severe disease and death months later, immunity may begin to wane and protection against milder and asymptomatic disease may drop over time. Studies also show that booster doses restore that immunity.

Public health officials in the Biden administration are on the “same page” when it comes to the benefits of booster shots, US Surgeon General Dr. Vivek Murthy said Sunday.

“The reality is that there is much more agreement here than I think people appreciate,” said Murthy when asked by Fox News’ Chris Wallace whether there was a split among experts like Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, and CDC Director Dr. Rochelle Walensky.

Murthy said that Fauci, Walensky and he all believe that vaccine immunity against Covid-19 can wane over time and they prefer the FDA and CDC to weigh in on both the efficacy and safety of booster shots.

“While we have now millions of people eligible for booster shots, we’re going through an FDA process and we’ll go through a CDC process to see if that eligibility should be widened,” Murthy said. “But the bottom line is all of us are on the same page about the strong protection that vaccines afford and we know that where boosters are indicated that they will be helpful to extending people’s protection against Covid-19.”

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