An independent advisory group to the Food and Drug Administration voted Tuesday in favor of authorizing the Covid vaccine made by drugmaker Novavax for adults ages 18 and older.
Twenty-one members of the committee voted yes, and none voted no, though one person abstained. Next, the FDA will decide whether to authorize the shot for emergency use, which would make it the fourth coronavirus vaccine available in the U.S. The FDA often follows the group’s recommendations.
If authorized, Novavax’s shot would be the only protein-based Covid vaccine distributed in the country. That formulation is more traditional than the mRNA shots from Pfizer and Modern. The FDA has approved several protein-based vaccines in the past, including one for hepatitis B and another for shingles.
Because of that, some of the FDA committee members think it might appeal to U.S. residents who have thus far chosen not to get vaccinated.
“Having a protein-based alternative may be more comfortable for some in terms of their acceptance of vaccines,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said during the meeting.
One-third of Americans are not fully vaccinated for Covid, and 22 percent have not received a single Covid vaccine dose, according to the Centers for Disease Control and Prevention.
Novavax’s vaccine appeared highly effective in its trial: It lowered the risk of symptomatic Covid by 90 percent in a group of more than 30,000 people in the U.S. and Mexico. But because the trial was conducted from December 2020 to February 2021, when the alpha variant was dominant, it did not determine the vaccine’s efficacy against the omicron variant.
“It is quite disappointing that we don’t have any data in the omicron era,” said Dr. Mark Sawyer, a committee member and infectious disease specialist at Rady Children’s Hospital in San Diego, though he added that the data “is quite similar to what we’ve approved in the past with other vaccines.”
The Novavax option
The World Health Organization authorized the Novavax vaccine for emergency use in December. It has also been authorized in Australia, the European Union, India, Indonesia, the Philippines, South Korea and the United Kingdom. Novavax said Tuesday that 744,000 doses have been administered worldwide as of April.
In Tuesday’s meeting, Marks said that although Americans have had other vaccine options for a while, “anything we can do to get people more comfortable to be able to accept these potentially life-saving medical products is something that we feel we are compelled to do.”
But some other experts questioned whether vaccine-hesitant people will think of Novavax any differently. The U.S. already discarded 82.1 million Covid vaccine doses from December 2020 through mid-May — more than 11 percent of the doses distributed by the federal government, according to CDC data.
“I’m a little skeptical about how many of the vaccine hesitant are just waiting for this vaccine and they’re going to be convinced that this is better for them than the vaccines that are currently available,” said Dr. Arthur Reingold, a committee member and the division head of epidemiology and biostatistics at the University of California, Berkeley, School of Public Health.
Novavax’s vaccine consists of two doses, given three weeks apart. It uses the purified spike protein from the coronavirus, along with an immune-boosting ingredient called an adjuvant, to stimulate the production of antibodies. By contrast, mRNA vaccines use a snippet of the coronavirus’ genome to instruct the body to produce the spike protein internally, which then prompts the development of antibodies.
Johnson & Johnson’s Covid vaccine, meanwhile, introduces a gene for the spike protein into the body via a genetically engineered common cold virus. But due to the risk of blood clots, that shot is only being offered to adults who refuse the other Covid vaccines or cannot receive them for medical reasons.
Experts raised questions about myocarditis
The Novavax trial identified five instances of myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the membrane surrounding the heart) within two weeks of vaccination, “raising concern for a causal relationship,” according to an FDA briefing document.
By comparison, the CDC identified 1,226 reports of myocarditis out of 296 million Pfizer and Moderna vaccinations from December 2020 to June 2021. But committee experts disagreed about whether it’s fair to compare myocarditis risk across vaccine platforms, since Novavax hasn’t been distributed as widely yet.
“It would be, at this stage, difficult to say it occurs more frequently with one vaccine platform than another,” said Dr. Cody Meissner, chief of the pediatrics infectious disease division at Tufts University School of Medicine.
The CDC identified around 5,000 cases of myocarditis among 1.45 million people diagnosed with Covid from March 2020 to February 2021 — a much higher rate than has been observed in connection to any vaccine so far.