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Despite clearing a key FDA committee, it could be several months before the Novavax COVID-19 vaccine receives emergency use authorization and is available to the public. Patrick van Katwijk /Getty Images
  • The FDA’s vaccine advisory committee recommended authorization of Novavax’s protein subunit COVID-19 vaccine.
  • Protein subunit vaccines utilize a more traditional development process, similar to existing vaccines for pertussis (whooping cough) and hepatitis B.
  • The vaccine is 90.4 percent effective against laboratory-confirmed, symptomatic infection, and 100 percent effective against moderate and severe disease.
  • Even though the FDA vaccine advisory committee voted to recommend emergency use authorization (EUA), the FDA will need additional time to review manufacturing changes.
  • There is no confirmed release date for the Novavax COVID-19 vaccine.

Novavax’s COVID-19 vaccine has cleared the Food and Drug Administration’s (FDA) vaccine advisory committee, but still has more waiting to do as the agency reviews changes to the company’s manufacturing process.

After an all-day meeting on June 7, the FDA’s independent panel of vaccine experts voted 20 to 0, with one abstention, to recommend that the vaccine receive an emergency use authorization (EUA).

The FDA normally follows the committee’s recommendation, but it is under no obligation to do so.

As a result of the manufacturing changes, the agency may take longer to authorize Novavax’s vaccine than it did with the Pfizer-BioNTech, Moderna, and Johnson & Johnson vaccines, all of which received approval shortly after getting the thumbs up from the advisory committee.

In a statement to CNBC, the FDA said that Novavax notified it of changes to its manufacturing process several days before the advisory committee was set to discuss data on the vaccine’s safety and efficacy.

The FDA did not provide a timeline for when it would complete its review of the vaccine.

This is not the first time Novavax has struggled to move its vaccine forward. The company has also faced supply chain and clinical trial delays.

While this vaccine has been slow to get out of the gate, supporters say this “more traditional” vaccine still has a role to play in the country’s ongoing fight against coronavirus.

Novavax’s vaccine is a two-dose regimen, with the doses given 21 days apart — similar to the primary series regimens for the mRNA-based Pfizer-BioNTech and Moderna vaccines.

In contrast to the mRNA vaccines, which are based on a newer vaccine technology, Novavax’s product uses a more traditional technology.

This protein subunit vaccine delivers purified copies of the spike protein of SARS-CoV-2, the coronavirus that causes COVID-19. This generates a protective immune response without causing illness. The vaccine also contains an adjuvant, which helps stimulate the immune response.

Effective subunit vaccines have also been developed for pertussis (whooping cough), hepatitis B, and other diseases, giving this type of vaccine a strong track record.

At the FDA meeting, Novavax presented data showing that its vaccine was safe and effective.

In addition, a study published earlier this year in the New England Journal of Medicine found that the vaccine was 90.4 percent effective against laboratory-confirmed, symptomatic infection, and 100 percent effective against moderate and severe disease.

However, this study was done when the Alpha and Delta variants were circulating. Additional data will be needed to know how well the vaccine performs against the Omicron variant — and whether a booster will be needed, as has been the case with the mRNA vaccines.

Novavax’s chief medical officer, Dr. Filip Dubovsky, said at the FDA meeting that the company has data on the use of its vaccine as a booster and will apply later to the agency for authorization of a booster dose of its vaccine.

Data presented at the meeting also showed that the vaccine was safe, with similar side effects as the mRNA vaccines.

”Patients have generally fewer adverse reactions like pain at the injection site, fever, headache, etc. after vaccination [with Novavax] compared to mRNA vaccines,” said Matthew Frieman, Ph.D., an associate professor of microbiology and immunology at the University of Maryland School of Medicine. “This is great for people who are concerned about reactions to the mRNA vaccines.”

“This vaccine also doesn’t have PEG [polyethylene glycol], which is a chemical [used as a stabilizer] in the mRNA vaccines, and something people can be allergic to,” he added.

One potential safety concern raised during the FDA meeting is myocarditis — inflammation of the heart muscle.

Five cases of myocarditis were identified in people who received the Novavax vaccine during the clinical trials. Four of these were in younger men, which is similar to what occurs with the mRNA vaccines.

Although myocarditis after mRNA vaccination is more common in younger men, the overall risk of this side effect is small. Myocarditis also occurs after coronavirus infections, at a higher rate than after vaccination, according to some data.

At the meeting, the FDA asked the company to add myocarditis as a risk factor on its product insert.

Because the Novavax vaccine is coming onto the scene late in the pandemic — with the majority of vaccinated Americans receiving an mRNA vaccine — it’s not clear what role this vaccine will play in the country’s COVID-19 response going forward.

Dr. Stuart Cohen, the chief of infectious diseases at UC Davis Health in Sacramento, California, said in spite of the long road to approval for the Novavax vaccine, there is still benefit to providing an alternative vaccine that has similar efficacy as the mRNA vaccines

In addition, the Novavax vaccine may work as a booster for the mRNA vaccines, he said, because it stimulates the immune system in a slightly different way.

However, “the studies need to be done to actually determine whether that is a good idea,” said Cohen.

Some people also think that since Novavax is based on a more traditional vaccine technology, those who are hesitant to receive an mRNA vaccine may be more likely to roll up their sleeves for this one.

“I am hopeful that this [vaccine] will convince people hesitant to mRNA vaccination [to get vaccinated], for whatever reason they are hesitant,” said Frieman.

Cohen said his experience with the Novavax clinical trial suggests that some people may indeed prefer this vaccine over the mRNA vaccines.

“We were a site for the phase 3 clinical trial and the things that seemed to drive patients to enroll were the availability of a way to get vaccinated and the comfort with the technology,” he said.