CDC Votes to Allow Use of Omicron Vaccine Boosters

Sept. 1, 2022 — A panel of advisors to the CDC today supported use of vaccines designed to target both Omicron and the older variants of the coronavirus, a step that may aid a goal of a widespread immunization campaign before winter arrives in the U.S.

The CDC’s Advisory Committee on Immunization Practices voted 13-1 Thursday on two separate questions. One sought the panel’s backing for the use of a single dose of a new version of the Pfizer COVID-19 vaccines for people age 12 and older. The second question dealt with a single dose of the reworked Moderna vaccine for people age 18 and older.

The federal government wants to speed use of revamped COVID-19 shots, which the FDA on Thursday cleared for use in the U.S..

Once CDC Director Rochelle Walensky, MD, signs off on the panel’s recommendation – which come as soon as tonight – the new boosters will be available.

The FDA vote expands the emergency use authorization EUA for both Moderna and Pfizer’s original COVID-19 vaccines. The new products are also called “updated boosters.” Both contain two mRNA components of SARS-CoV-2 virus, one of the original strain  and another that is found in the BA.4 and BA.5 strains of the Omicron variant, the FDA said.

Basically, the FDA cleared the way for these new boosters after it relied heavily on results of certain blood tests that suggested an immune response boost from the new formulas, plus 18 months of mostly safe use of the original versions of the shots.

What neither the FDA nor the CDC has, however, is evidence from studies in humans on how well these new vaccines work or whether they are as safe as the originals. But the FDA did consider clinical evidence for the older shots and results from studies on the new boosters that were done in mice.

Committee member Pablo Sanchez, MD, of Ohio State University was the sole “no” vote on each question.  

“It’s a new vaccine, it’s a new platform. There’s a lot of hesitancy already. We need the human data,”  Sanchez said.

Sanchez did not doubt that the newer versions of the vaccine would prove safe.

“I personally am in the age group where I’m at high risk and I’m almost sure that I will receive it,” Sanchez said. “I just feel that this was a bit premature, and I wish that we had seen that data. Having said that, I am comfortable that the vaccine will likely be safe like the others.”

Sanchez was not alone in raising concerns about backing new COVID-19 shots for which there is not direct clinical evidence from human studies.

Committee member Sarah Long, MD, of Drexel University in Philadelphia, said during the discussion she would “reluctantly” vote in favor of the updated vaccines. She said she believes they will have the potential to reduce hospitalizations and even deaths, even with questions remaining about the data.

Long joined other committee members in pointing to the approach to updating flu vaccines as a model. In an attempt to keep ahead of influenza, companies seek to defeat new strains through tweaks to their FDA-approved vaccines. There is not much clinical information available about these revised products, Long said. She compared it to remodeling an existing home.

“It is the same scaffolding, part of the same roof, we’re just putting in some dormers and windows,” with the revisions to the flu vaccine, she said.

Earlier in the day, committee member Jamie Loehr, MD,  of Cayuga Family Medicine in Ithaca, NY, also used changes to the annual flu shots as the model for advancing COVID-19 shots.

 “So after thinking about it, I am comfortable even though we don’t have human data,” he said.

There were several questions during the meeting about why the FDA had not convened a meeting of its Vaccines and Related Biological Products Advisory Committee (regarding these specific bivalent vaccines. Typically, the FDA committee of advisors considers new vaccines before the agency authorizes their use. In this case, however, the agency acted on its own.

FDA said the committee considered the new, bivalent COVID-19 boosters in earlier meetings and that was enough outside feedback.

But holding a meeting of advisors on these specific products could have helped build public confidence in these medicines, Dorit Reiss, PhD, of the University of California Hastings College of Law, said during the public comment session of the CDC advisors’ meeting.

“We could wish the vaccines were more effective against infection, but they’re safe and they prevent hospitalization and death,” she said.

ACIP support anticipated

The Department of Health and Human Services anticipated the backing of ACIP and expects Walensky’s endorsement will follow. The Administration for Strategic Preparedness and Response  on Wednesday began distributing “millions of doses of the updated booster to tens of thousands of sites nationwide,” wrote Jason Roos, PhD,  chief operating officer for HHS Coordination Operations and Response Element, in a blog.

“Pending the CDC’s recommendation, people will soon be able to receive – at no charge – their updated COVID-19 booster shot containing an Omicron component,” Roos wrote. “These boosters will be available at tens of thousands of vaccination sites they’ve used previously, including local pharmacies, their physicians’ offices, and vaccine centers operated by state and local health officials.”

Sources:

Hearing, CDC Advisory Committee on Immunization Practices, Sept. 1, 2022.

FDA: “FDA’s Critical Role in Ensuring Supply of Influenza Vaccine.”

Administration for Strategic Preparedness and Response: “ASPR Begins Distributing Updated COVID-19 Boosters.”