What to Know About Novavax, the Fourth COVID Vaccine Approved by the CDC

A fourth COVID vaccine will be available in the US within weeks. The shot, created by Maryland-based biotechnology company Novavax, was authorized for emergency use by the FDA on July 13. And as of July 19, Centers for Disease Control and Prevention director Rochelle Walensky, MD, gave Novavax the official stamp of approval as well, clearing it for use in the United States.

"Today, we have expanded the options available to adults in the U.S. by recommending another safe and effective COVID-19 vaccine," Dr. Walensky said in a CDC statement. "If you have been waiting for a COVID-19 vaccine built on a different technology than those previously available, now is the time to join the millions of Americans who have been vaccinated. With COVID-19 cases on the rise again across parts of the country, vaccination is critical to help protect against the complications of severe COVID-19 disease."

The two-dose vaccine is recommended for adults ages 18 and older, with a three-week wait period between the initial and second dose of the series. If you're considering Novavax, or are just curious about the new vaccine, we spoke to an infectious disease expert to better understand the efficacy and necessity of the fourth vaccine.

"I think the menu for COVID vaccine should be as large as we can make it because there are important problems we still have to solve," says Amesh Adalja, MD, senior scholar at the Johns Hopkins University Center for Health Security. Those problems, he says, include finding the best booster strategy and combating the anti-vaccination movement which has "maligned the mRNA vaccines," causing vaccine hesitancy (about 1 in 3 Americans remain unvaccinated, per CNN).

A new vaccine provides scientists and citizens with another option. "From a scientific standpoint, I think the fact that we have another tool to be able to mix and match with other vaccines to come up with the optimal cocktail of boosters and an initial vaccine series is going to be important," Dr. Adalja adds.

"Having multiple types of vaccines offers more options and flexibility for the public, jurisdictions, and vaccine providers," the CDC said in a recent statement.

"The chief difference that this is a protein-based vaccine, as Moderna and Pfizer vaccines are mRNA-based and the Johnson & Johnson uses a different virus to deliver the spike protein of SARS-CoV-2," Dr. Adalja says. Novavax is a vaccine that delivers the spike protein "directly in the form of a protein," which produces an immune response in the body that will protect against a future interaction with the virus. It's a more traditional approach in that it uses the same technology used in influenza vaccines, HPV, hepatitis B, and shingles.

That being said, because the Novavax vaccine uses a spike protein based on the "ancestral" strain of the virus (Omicron), "it will likely have difficulty in preventing all infections from Omicron variants, just like the current other current vaccines," Dr. Adalja says. But one thing that differs in Novavax is that the spike protein is coupled with an adjuvant, "a substance that stimulates the immune system," Dr. Adalja says, which could play a role in how broad the response is in terms of protection against new variants that differ from the vaccine strain.

It also can be stored in standard refrigeration, which is unique to Novavax, and may help with distribution because it's easier to transport and store in low-income settings

In clinical trials, the Novavax vaccine had an 90.4% overall efficacy rate, per Novavax. The company also announced that the vaccine shows "broad" immune response to variants like Omicron sub-varients BA.4 and BA.5.

Common side effects are similar to other vaccines, including fatigue, tenderness or pain at the injection site, headache, and muscle pain. The FDA also recently published data showing the vaccine may cause myocarditis and pericarditis, albeit rarely, news that caused the company's stock price to dip, reports Science. (Myocarditis and pericarditis is "the inflammation of the heart muscle" and "inflammation of the lining outside the heart," respectively, per the CDC — a side effect also reported after the use of some mRNA vaccines.)

Still, chief safety officer, Denny Kim told FDA advisers: "We believe that the totality of the clinical evidence here is not enough to establish an overall causal relationship with the vaccine," as reported by the AAAS. Novavax is reportedly monitoring these cases. What's more, the vaccine has already been approved in more than 170 countries, per CNBC.

Now that the vaccine has been green lit, it should be available within "the coming weeks," according to the CDC press release. On July 11, the Biden administration announced it had already secured 3.2 million doses of the Novavax vaccine.

According to WHO, the vaccine is not yet recommended for people younger than 18 years of age, until enough data is available to be reviewed. But Novavax president and CEO Stanley Erck Novavax spoke with CNN and said the company hopes to offer the vaccine to children as young as two later this year, once data on its effectiveness on kids becomes available.

And while the vaccine has been only been approved as a primary vaccine series thus far, Novavax also hopes to receive authorization to use its vaccine as a booster to the others, like Moderna and Pfizer. "We've talked with the FDA quite a bit about this," Novavax president and CEO Stanley Erck told CNN. "I believe the FDA will be addressing that approval within weeks."

— Additional reporting by Melanie Whyte