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The Food and Drug Administration on Wednesday authorized the Covid-19 vaccine developed by Novavax, a small Maryland biotech firm, for people 18 and over, voicing hope that the availability of a more traditional vaccine might help convince those skeptical of the Covid shots using new mRNA technology to get inoculated.

As with other Covid vaccines, the Novavax shot will be free to consumers, because the U.S. government will purchase the doses. But before the vaccine will be widely available, it must also be recommended by the director of the Centers for Disease Control and Prevention. That recommendation will likely follow a July 19 meeting of an expert committee convened by the CDC.

“Authorizing an additional Covid-19 vaccine expands the available vaccine options for the prevention of Covid-19, including the most severe outcomes that can occur such as hospitalization and death,” said FDA Commissioner Robert M. Califf in a prepared statement. “Today’s authorization offers adults in the United States who have not yet received a COVID-19 vaccine another option that meets the FDA’s rigorous standards for safety, effectiveness and manufacturing quality needed to support emergency use authorization.”


The U.S. has received 3.2 million doses of the vaccine that are ready to be shipped to states once the vaccine is authorized and recommended by the CDC.

“Today’s FDA emergency use authorization of our COVID-19 vaccine provides the U.S. with access to the first protein-based COVID-19 vaccine,” said Stanley C. Erck, Novavax’s CEO. “This authorization reflects the strength of our COVID-19 vaccine’s efficacy and safety data, and it underscores the critical need to offer another vaccine option for the U.S. population while the pandemic continues.”


Unlike the vaccines from Pfizer/BioNTech and Moderna, the Novavax vaccine has had a bumpy path to the market. Novavax received $1.6 billion in support from the U.S. government’s Operation Warp Speed project in July 2020. At the time, the hope was that the company might begin making a vaccine by the beginning of 2021. But while the Moderna and Pfizer/BioNTech shots released data in November of 2020, results were not available for the Novavax vaccine until June of 2021.

There were also questions about the ability to produce the vaccine in large amounts. The original deal between Novavax and Operation Warp Speed would entitle the U.S. to 100 million doses of the vaccine. In the press release announcing the vaccine’s emergency use authorization, FDA officials emphasized that the vaccine had not only met the FDA’s bar for safety and efficacy but also “assessment of the manufacturing processes and information.”

In June, a panel of FDA advisers voted 21 to 0, with one abstention, that the Novavax vaccine’s benefits outweigh its risks.

One hope expressed at that meeting was that the existence of another vaccine would help convince some of the millions of Americans who have chosen not to be vaccinated to change their minds. The Pfizer and Moderna vaccines work by a new mechanism in which messenger RNA is used to lead cells to create a protein on the virus’ surface that the immune system can recognize. The Novavax vaccine instead produces this protein in vats of insect cells and delivers it to patients with a chemical adjuvant that spurs the immune system to recognize it.

A similar process is used to make an influenza vaccine that is manufactured by Sanofi.

At the FDA meeting, Peter Marks, the director of the FDA’s Center for Biologics Evaluation, said he hoped that the existence of such an option might convince the vaccine hesitant.

“We do have a problem with vaccine uptake that is very serious in the U.S., and anything we can do to make people more comfortable to accept these potentially lifesaving products is something we are compelled to do,” Marks said.

“Optimism that the Novavax vaccine will have a significant impact on the number of unvaccinated Americans is misplaced,” Jason Schwartz, an associate professor at the Yale School of Public Health, told STAT.

“A small number of people might have been waiting for a vaccine that doesn’t involve mRNA technology or lacks the remote links to fetal tissue associated with the development of the currently available vaccines, but the vast majority of those unvaccinated have made their choice for unrelated and deeply ingrained reasons,” Schwarz said.

He said it would be a good thing if the Novavax authorization moves even 1% to 2% of unvaccinated people to become vaccinated, but called that “the best-case scenario.”

The new authorization is for a series of two shots, separated by three weeks, in unvaccinated people. It does not cover the use of the Novavax vaccine as a booster shot, which the agency will need to evaluate separately.

The authorization is based on a randomized, blinded and placebo-controlled study conducted in the U.S. and Mexico before the current Omicron variant was dominant. In the study, 17,200 people received the vaccine and 8,300 a saline placebo, with 17 cases of Covid-19 occurring in the vaccine group and 79 cases in the placebo group. That means the vaccine had 90.4% efficacy, although that efficacy is expected to be lower for current variants.

Aside from the side effects expected of a vaccine, such as headaches or fevers, the Novavax vaccine, like the mRNA vaccines made by Pfizer and Moderna, is linked to an increased risk of myocarditis and pericarditis, which are an inflammation of the heart or its lining. This side effect is rare and most often occurs in adolescent males and young men, who are at elevated risk for the condition generally.

The safety information provided with the vaccine will say that if they occur, myocarditis symptoms begin within 10 days following vaccination and that vaccine recipients should seek medical attention if they experience chest pain, shortness of breath, or the feeling of a fluttering or pounding heart.

Another vaccine, from Johnson & Johnson, was also authorized but its use has been limited by the FDA because of a rare side effect.

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