FDA Grants Emergency Use Authorization for Novavax's COVID-19 Vaccine

The new two-dose series may open up vaccines to people who were previously hesitant about other options.

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The Novavax COVID-19 vaccine has been authorized for emergency use by the U.S. Food and Drug Administration (FDA), the agency announced Wednesday. The two-dose shot is intended for use in people 18 years of age and older.

Novavax's vaccine is the fourth shot to be authorized for use in the U.S. It uses a technology different than Pfizer and Moderna's mRNA science, and Johnson & Johnson's viral vector vaccine. Instead, it's what's known as a protein-based vaccine—and the technology could open up vaccines for people who had previously been hesitant to get other authorized options.

"We believe our vaccine offers a differentiated option built on a well-understood protein-based vaccine platform that can be an alternative to the portfolio of available vaccines to help fight the COVID-19 pandemic," Stanley C. Erck, president and chief executive officer of Novavax, said in a January 2022 news release.

Here's what to know about the newly-authorized Novavax COVID-19 vaccine.

How the Novavax COVID-19 Vaccine Works

Novavax's vaccine consists of two doses given three weeks apart. The vaccine is known as a subunit vaccine or a protein subunit vaccine, meaning it contains only specific parts of the virus that provide the best way to stimulate the immune system.

"Instead of the entire pathogen—or virus, in this case—subunit vaccines include only components, or antigens, that are most effective in stimulating the immune system," Robert Glatter, MD, an emergency room physician at Lenox Hill Hospital, told Health. "This type of COVID-19 vaccine contains harmless spike proteins. Once your immune system recognizes the spike proteins, it then produces antibodies and specialized white blood cells to serve as a second line of defense."

All current vaccines hinge on that important spike protein in the SARS-CoV-2 virus—but while other vaccines deliver instructions to the body's cells to produce the protein, the Novavax vaccine delivers the proteins directly.

"The essential difference between the two types of vaccine is that the Novavax product is the spike protein itself—the protein subunit—whereas the mRNA vaccines train your own cells to produce the spike protein, which is the message transmitted by the messenger RNA," William Schaffner, MD, professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center, told Health.

All vaccines authorized for use to prevent COVID-19 do not contain any live parts of the virus, and cannot cause COVID-19.

The Novavax vaccine also includes an ingredient called an adjuvant, which helps create a stronger immune response to the vaccine. This is important because antigens alone are not sufficient for long-term immunity.

Adjuvants—which sometimes include aluminum or squalene, a colorless liquid—have been used in vaccines in the U.S. for decades, according to the Centers for Disease Control and Prevention (CDC). They were developed to target specific components of the body's immune response so that protection against disease is stronger and longer lasting, the CDC explains. In other words, adjuvants help vaccines work better.

"Vaccines containing adjuvants are tested for safety and effectiveness in clinical trials before they are licensed for use in the U.S., and they are continuously monitored by CDC and FDA once they are approved," said Dr. Glatter.

How Novavax’s Vaccine May Help Increase Vaccination Rates

Unlike mRNA technology, protein subunit vaccines, or protein-based vaccines, are not new. The first protein subunit vaccine approved in the U.S. was the hepatitis B vaccine, according to the National Institute of Allergy and Infectious Diseases (NIAID).

Vaccines made to prevent human papillomavirus (HPV) are also based on protein subunit vaccines—those vaccines use proteins on the outer shell of HPV that closely resemble the virus, the NIAID said.

A more tried-and-true method of immunization may be what many Americans have been waiting for. According to a February 2022 Ocugen/Harris Poll, 73% of Americans said they'd "like to see additional COVID-19 vaccines be available that are developed from a more traditional method."

Those sentiments were true for parents who had not yet vaccinated their children, as well. Data showed that 40% of parents with unvaccinated children under 18 said they'd be more likely to vaccinate with a "more traditional method," and 38% of parents with children under 5 years old said "they definitely/probably will not get their children age 5 and under vaccinated with the existing vaccines if/when available."

In a press release shared Monday, Erck said that the U.S. government has secured 3.2 million doses of the Novavax COVID-19 vaccine, which is likely to help with this issue. "We are pleased to come one step closer to potentially offering our vaccine to physicians, healthcare organizations, and consumers who have been awaiting a protein-based vaccine option," he said.

How Effective is the Novavax Vaccine—And Will it Protect Against Omicron?

According to the World Health Organization (WHO), the efficacy of the Novavax vaccine against mild, moderate, and severe disease from COVID-19 is 90%.

"In clinical trials, the vaccine's efficacy against infections has reached as high as 96%," added Dr. Glatter. "One important caveat is that Novavax's Phase III trial took place before the emergence of Delta and Omicron."

The vaccine was at least 80% effective against the Alpha variant, but its efficacy against infection declined to 50 to 60% against Beta.

"The bottom line is that we just don't know how Novavax's vaccine will hold up against the omicron variant," said Dr. Glatter. "However, at the time, data does suggest that a Novavax booster shot increases antibody levels against omicron more effectively than Pfizer or Moderna booster shots."

Novavax has also said that they are developing an Omicron-specific vaccine that will be ready for supply this fall, in accordance with recommendations by the FDA's advisory committee. The vaccine, according to Novavax, "induces immune response against Omicron variants, including BA.4 [and BA.5]."

When Will the Novavax Vaccine Officially Be Available in the U.S.?

The Novavax vaccine is available in the U.K, Germany, New Zealand, and Australia. And though it's been authorized for emergency use by the FDA, there are still a few steps before it's officially available for use in the U.S.

Now, the CDC's Advisory Committee on Immunization Practices (ACIP) must decide whether to recommend the vaccine—and then CDC director Rochelle Walensky, MD, must sign off on the recommendation.

According to CNN, the ACIP is set to meet to discuss the Novavax COVID-19 vaccine on July 19.

If and when the CDC gives the vaccine the green light, individuals ages 18 years and older will be able to get the shot as a primary series. It's not yet known whether the shot will also be able to act as a booster dose.

"I anticipate that the Novavax vaccine will be available to any adult who wishes to get vaccines," said Dr. Schaffner. "I do not know whether it could be an effective booster for those who previously had received mRNA vaccines. Data would have to be developed to support that use."

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