The FDA is expected to authorize Novavax, a new COVID-19 vaccine, though it's still under review.

Novavax will be the first protein-based vaccine for COVID-19 available in the US, though the technology has been around for decades.

The same committee earlier this month endorsed Novavax, a protein-based COVID-19 vaccine, for authorization.

The percentage of American adults who answered the poll who said they would "definitely not" get a COVID-19 vaccine ranged from 15% in December 2020 to 17% April 2022.

However, some scientists are hopeful that Novavax may one day be used as a booster dose in combination with other vaccines, and that its primary series may fill a need for a more traditional and potentially equally effective COVID-19 vaccine.

"It's good to have a vaccine on board like Novavax because it's another option for those that might have contraindications to the other vaccine platforms," Ross Kedl, a professor of immunology and microbiology at the University of Colorado Anschutz Medical Campus, said in an email.

Novavax is a COVID-19 vaccine that uses a more traditional protein-based technology, unlike the other vaccines currently available in the US: Pfizer-BioNTech and Moderna use mRNA technology, and Johnson & Johnson is a viral-vector vaccine. .

In the Novavax vaccine, a purified protein of the virus is mixed with what's called an adjuvant -- additives that "wake up the immune response and tell it to take this target seriously," Kedl said.

"Specifically, Novavax is very similar to the hepatitis B vaccine" that most of us receive as children, Wortmann said.

"mRNA vaccines skip that step because they turn each individual into their own vaccine manufacturer," he said.

"The mRNA platform is far more modifiable than what Novavax does," he said.

The US government had originally planned to purchase 110 million doses of the vaccine, The New York Times reports, but the US has a sufficient supply of COVID-19 vaccines for primary doses and booster shots. 

Once there's data on using a vaccine like Novavax with mRNA vaccines, "There may be people that received three or four of the mRNA vaccines and might be interested in trying a different vaccine as part of a mix-and-match strategy," Wortmann said.