A Novavax Booster Is Here. But Who Will Take It?

Adults 18 and older in the United States can now get Novavax’s COVID-19 vaccine as a first booster dose instead of the updated bivalent COVID booster shot from Pfizer or Moderna.

On October 19, the U.S. Food and Drug Administration (FDA) authorized the Novavax booster for adults over the age of 18 who are at least six months out from getting their primary COVID vaccine series.

Shortly after, the Centers for Disease Control and Prevention (CDC) also signed off on the decision.

Before the recent authorization, Novavax’s vaccine was only authorized as a two-dose primary series. According to CDC data, around 38,000 people have received Novavax’s vaccine as a primary series in the U.S.

Linda Yancey, MD, an infectious disease specialist at Memorial Hermann Health System in Southeast Texas, told Verywell that the Novavax shot is “another option for people wanting to protect themselves against COVID,” and that the shot “can be given to people who cannot get other vaccines for medical or accessibility reasons.”

Here’s everything you need to know about the Novavax COVID booster shot, including how to find out if you’re eligible to get it.

Who Can Get a Novavax COVID Booster?

According to the FDA, the Novavax booster vaccine is approved for people 18 years of age and older who are six months out from their first two COVID shots. People who received the Pfizer, Moderna, or J&J shots as their primary series can get Novavax as their first booster if they choose.

The Novavax booster will also be available in cases where an FDA-authorized mRNA bivalent COVID-19 booster vaccine is not accessible to someone or the right choice medically for them.

In addition, people who would rather not or cannot get either Pfizer’s or Moderna’s mRNA vaccines for their primary series and first booster can get the Novavax COVID vaccine instead.

Anne Liu, MD, a board-certified, fellowship-trained specialist in allergy/immunology and infectious disease at the Stanford University School of Medicine, told Verywell that providers are hoping the authorization “will increase the reach of vaccination to the many folks out there who are not getting mRNA vaccines.”

However, Yancey noted that the Novavax booster is not available for children or for people who have already had one booster.

How Is Novavax Different?

A vaccine like Novavax is considered a protein subunit vaccine. It contains pieces (proteins) of the virus that causes COVID (you’ve heard it called the “spike” protein).

According to Yancey, a protein subunit vaccine “is a purified immunogenic protein” which is a “viral protein that we know will generate a strong immune response and give high-level protection against the virus.”

Liu explained that the protein subunit vaccines also contain an ingredient called an adjuvant, “which is something that stimulates the immune system to recognize the protein piece as something to form an immune response against,” and added that it’s “a much older vaccine technology.”

Since an adjuvant is used to strengthen the immune response and allow the immune system to recognize and respond to the spike protein, in the end, the immune system can respond quickly to the virus spike protein and protect you against COVID.

Health experts add that this type of vaccine is safe because the protein that’s used is generated in a lab—there is no actual virus present in either the vaccine or in the manufacturing process.

“The protein subunit in the Novavax vaccine cannot give you an infection and cannot replicate,” said Liu. “We have been using other vaccines for years that are based on protein subunit technology, including hepatitis B and tetanus.”

Novavax vs. Moderna, Pfizer, and J&J

The technology it uses means that Novavax is different from the COVID vaccines we’ve had so far.

“[Pfizer and Moderna] deliver a recipe to our cells that then generates the viral protein using our own cells’ building blocks.” Yancey said, adding that the J&J shot is an adenovirus vaccine that delivers the viral protein “in an inactivated adenovirus.” (That means it’s not a live virus.)

According to Yancey, despite their differences, these vaccines have the same basic mechanism: “to show the viral protein to the immune system so that it can be forewarned and produce protective antibodies against COVID.”

How Well Does Novavax Work?

In Novavax’s Phase 3 clinical trial, the vaccine was found to be 90% effective against mild, moderate, and severe COVID disease. The trial included more than 15,000 participants over the age of 18.

In a report, the FDA concluded that the known and potential benefits of the Novavax vaccine outweigh any potential risks.

Liu noted that the initial data reviewed by the FDA regarding Novavax’s efficacy was collected before Omicron became the predominant COVID variant. That means that Novavax’s efficacy against Omicron, its subvariants, and new variants, is unknown.

“It was tested before Omicron was dominant,” said Liu. “[But] the data we have during Omicron is from antibody measurements, and shows that this vaccine, with boosting, can produce high levels of neutralizing antibodies against Omicron.”

A news release by Novavax on October 12 stated that new data shows the booster dose of the vaccine produced robust antibodies against several Omicron variants—including BA.1, BA.2, and BA.5—in adults and adolescents.

Novavax has ongoing trials to study the efficacy of its vaccine as an effective booster against COVID variants like BA.4 and BA.5.

Is Novavax Safe?

Liu said that the Novavax vaccine appears to be safe with few side effects. There were a few cases of heart inflammation called myocarditis reported in male clinical trial participants, but they were mild and easily treated.

“It’s not clear whether those cases were caused by the vaccination,” Liu said. “The rate of myocarditis in clinical trial participants was 0.007% in vaccine recipients and 0.005% in placebo recipients. Myocarditis from COVID-19 is much worse and frequent than myocarditis associated with vaccinations.”

Should You Get a Novavax Booster?

Experts say that there are a few reasons why people may want to get a Novavax booster instead of the bivalent boosters by Pfizer and Moderna.

One reason is that they have concerns or doubts about mRNA vaccines—especially since there is a lot of misinformation about the shots online. For example, some people believe that mRNA vaccines contain microchips, alter your DNA, can give you COVID, or have dangerous ingredients in them—all of which are false.

“Others are worried for other reasons,” said Liu. “There sure is a lot of misinformation circulating about the mRNA vaccines.”

Liu added that some people might want to get a Novavax booster because they had an allergic-type reaction or other side effects to the existing mRNA vaccines.

“Giving people more choices is seldom a bad thing,” Yancey said.

More people getting vaccinated will help control the spread of the virus this winter and may help keep people out of the hospital, which will lessen the strain on an already burdened healthcare system.