Novavax's COVID-19 Vaccine: Your Questions Answered

[Originally published: July 20, 2022. Updated: May 20, 2025.]

Note: Information in this article was accurate at the time of original publication. Because information about COVID-19 changes rapidly, we encourage you to visit the websites of the Centers for Disease Control & Prevention (CDC), World Health Organization (WHO), and your state and local government for the latest information.

The Novavax vaccine is one of three vaccines available in the U.S. for the prevention of COVID-19 and the only one that does not use the relatively new mRNA vaccine technology. Instead, it relies on a traditional virus-blocking technology that’s been used against other diseases.

The Food and Drug Administration (FDA) granted the Novavax vaccine full approval in May 2025, but added new restrictions to the shot, which was previously available under a 2022 emergency use authorization (EUA). The FDA is now approving the vaccine for people 65 years and older, and those ages 12 through 64 who have at least one health condition that puts them at increased risk for a severe outcome from COVID.

The 2024-2025 Novavax vaccine, sold in the U.S. under the brand name Nuvaxovid™, became available in August 2024. The vaccine targets a SARS-CoV-2 variant called JN.1, which was the dominant strain in May 2024 and was surpassed by a collection of other Omicron virus strains. (But experts had predicted that updated vaccines from Novavax, Pfizer, and Moderna would likely cover other Omicron variants that might emerge in the year to follow.)

All three companies are working on updated shots for fall 2025, while advisers to the CDC are debating new recommendations the agency might make.

“A non-mRNA option is good news for many reasons,” said F. Perry Wilson, MD, a Yale Medicine nephrologist and epidemiologist, when the original Novavax vaccine was authorized. One is that this is an additional vaccine choice that may be acceptable to Americans who are not fully vaccinated, he explained. Even though the Pfizer-BioNTech and Moderna mRNA vaccines are safe and highly effective, “we’ve heard a lot of people say the reason they've chosen not to get an mRNA vaccine is because the mRNA technology is relatively new and it hasn't been tried on a wide scale before.”

There are practical reasons as well. “It’s ideal to have more than one or two companies being th e sole providers of vaccines,” Dr. Wilson says. “We know how supply chains can get disrupted, and we want to make sure there's adequate vaccine available. We also want multiple production lines that potentially can be updated to address new variants and meet the challenges as they come.”

Here are some facts you should know about the Novavax vaccine.

Though COVID vaccines may utilize different delivery mechanisms, the end result is the same: cells in the body recognize that a spike protein (the spikes you see sticking out of the coronavirus in pictures) doesn’t belong, and the immune system reacts by activating immune cells and producing antibodies to attack the real virus if you get exposed.

But, unlike the other vaccines, Novavax directly injects a version of the spike protein, along with another ingredient that also stimulates the immune system, into the body, leading to the production of antibodies and T-cells. (It injects a version of the spike protein that has been formulated in a laboratory as a nanoparticulate that does not have genetic material inside and cannot cause disease.)

“I often tell people, imagine an eggshell without an egg in it. That’s what it is,” Dr. Wilson says.

The Novavax vaccine is a traditional one compared to the other vaccines. Its technology has been used before in vaccines to prevent such conditions as shingles, human papillomavirus, and DTaP (diphtheria, tetanus, and pertussis), among others.

The FDA approved the vaccine for people 65 years and older, and those ages 12 through 64 who have at least one health condition that puts them at increased risk for a severe outcome from COVID.

The most commonly reported side effects by vaccine recipients in the clinical trial were pain/tenderness, redness and swelling at the injection site, fatigue, muscle pain, headache, joint pain, nausea/vomiting, and fever. There is a remote chance that the vaccine could cause a severe allergic reaction, which would usually occur within a few minutes after the immunization. You should not get the Novavax vaccine if you’ve had a severe allergic reaction to a previous dose of it, or a severe reaction to any of the ingredients in the vaccine.

Approximately 21,000 vaccine recipients had at least two months of safety follow-up after their second dose, according an FDA statement.

While the Novavax vaccine is available to those who are eligible, the 2025 FDA approval requires Novavax to complete research including studies that could provide information about whether the shot is associated with several heart conditions.

Myocarditis, a rare form of inflammation of the heart muscle, occurred in a handful of Novavax clinical trial participants, all of whom were men. Novavax says “there is insufficient evidence to establish a causal relationship" between the vaccine and the condition. A committee that advised the FDA to authorize the Novavax vaccine decided the benefits of vaccination outweigh the risks of developing heart inflammation.

But, the Fact Sheet for Recipients and Caregivers says that in most people who have developed myocarditis or pericarditis (inflammation of the outer lining of the heart), symptoms began within 10 days following vaccination. It says vaccine recipients should seek medical attention right away if they experience any of the following symptoms: chest pain, shortness of breath, and/or feelings of having a fast-beating, fluttering, or pounding heart.

Similar rare reports have risen around the mRNA vaccines, and the FDA has issued a warning label on both the Pfizer and Moderna vaccines regarding myocarditis and pericarditis in adolescents and young adults. With the mRNA vaccines, the inflammation, in most cases, gets better on its own without treatment. But anyone experiencing heart symptoms after vaccination should seek medical attention.

As to whether people should be concerned about the risk, he says, “The risk of myocarditis is higher from COVID than it is from any of the COVID vaccines.”

The approval was based on the vaccine’s Phase 3 clinical trial data that showed it to be safe and effective for the prevention of COVID-19. Trial results, published in The New England Journal of Medicine, showed it to have 90.4% overall efficacy.

The FDA authorization for the updated 2024-2025 Novavax vaccine was based on non-clinical data that demonstrated broad cross-neutralizing antibodies against multiple variant strains, according to the Novavax company.

As with other COVID vaccines, breakthrough cases, in which someone who is vaccinated still gets infected with COVID, remain a reality.

“You're still going to see transmission of COVID, even among vaccinated people,” Dr. Wilson says. “But importantly, what we’re counting on the vaccines for is to reduce hospitalizations and deaths. That’s where I think the real benefit is going to come from, in reducing the burden on our hospitals and saving more lives over time.”

Additional information about the Novavax vaccine is available on the FDA’s Novavax 2024-2025 vaccine fact sheet.

Information provided in Yale Medicine articles is for general informational purposes only. No content in the articles should ever be used as a substitute for medical advice from your doctor or other qualified clinician. Always seek the individual advice of your health care provider with any questions you have regarding a medical condition.