The Novavax shot is a protein-based vaccine from traditional technology used against influenza and shingles. Many experts are eager to add another vaccine to the toolbox, particularly because the Johnson & Johnson shot is now recommended only for people who cannot or will not take messenger RNA vaccines.
“It’s important to have choices in vaccine platforms in a pandemic that is constantly evolving,” said Gregory Poland, director of the Mayo Clinic’s Vaccine Research Group and a paid consultant to Novavax.
But Novavax’s two-shot regimen is likely to have a limited impact as it arrives more than a year after other highly effective vaccines became available. Most of the population eligible for the shot — people 18 and older — are already vaccinated. About 27 million adults in the United States have not received any shot, according to data from the Centers for Disease Control and Prevention.
Experts on the committee noted that data supporting the vaccine’s authorization was old, showing its performance against an earlier iteration of the virus, before the current variants arose.
Bruce Gellin, chief of global public health strategy at the Rockefeller Foundation, abstained from voting but said he was giving the vaccine a “conditional yes.” He said the vaccine was shown to be generally safe and effective when clinical trials were conducted but that “we don’t know whether that is true today.” He said it was important to monitor the vaccine’s performance as it comes into use.
Given that other safe, effective vaccines are available, the panel debated whether it was necessary to authorize another option. Some committee members expressed skepticism about whether vaccine hesitant people would embrace the new shot.
But an FDA official stressed the importance of having options.
“Having a protein-based alternative may be more comfortable for some in terms of their acceptance of vaccine,” said Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research. “I will use this as a moment on the bully pulpit to say: We do have a problem with vaccine uptake that is very serious in the US, and anything we can do to make people more comfortable to accept these potentially lifesaving products is something we are compelled to do.”
The first vaccines to be authorized in the United States — from Pfizer and its German partner, BioNTech, and from Moderna — were based on messenger RNA technology, which instructs the body’s cells to build proteins that teach the immune system to halt the coronavirus. The technology had been under development for years, but the pandemic was the first time it was authorized — and the shots have now been widely used.
People who can’t or won’t take the mRNA vaccines may embrace the Novavax shots, but the ultimate use of the vaccine is probably as a booster. Going forward, the company plans to seek authorization for the shot as a booster and for use in adolescents and children.
The Novavax vaccine was shown to be 90 percent effective in a clinical trial run before the emergence of the omicron variant of the coronavirus. The results were announced a year ago, but the vaccine has repeatedly been delayed by manufacturing challenges.
“It is disappointing … that we don’t have more updated information, because we’re looking at the efficacy against strains that don’t exist anymore,” said advisory committee member Eric J. Rubin, an infectious-disease specialist at Brigham and Women’s Hospital in Boston. Even so, he said the case for the vaccine was “pretty compelling” considering some people who have avoided mRNA vaccines have shown interest in Novavax.
The regulatory issues regarding manufacturing are among the reasons for the delay in authorizing the shot from Novavax, which submitted its request for emergency authorization in January. Questions had arisen about why it has taken so much longer for the shot to reach the US market. The Novavax vaccine is already authorized in dozens of countries, including Japan and Britain.
Marks, of the FDA, said the agency doesn’t follow the lead of other countries, including on manufacturing.
“We take manufacturing very seriously,” Marks said, adding that the FDA has “a very high standard,” which is why it sometimes is referred to as a gold standard.
The FDA’s analysis identified five cases of heart inflammation happening shortly after vaccination among 40,000 people in the company’s trials, raising concern that the shot could carry the same rare risk as mRNA vaccines. Novavax executives pushed back on the FDA’s concern, noting that a company analysis showed that rates of the cardiac conditions myocarditis and pericarditis were exceedingly low and about the same in the group that received the vaccine and in study participants receiving a placebo.
“I think the story is incompletely written here, and we need to more fully understand what is going on,” said Filip Dubovsky, Novavax’s chief medical officer.
The Novavax coronavirus shot was one of six candidates backed by Operation Warp Speed, the federal program established to accelerate vaccine development. The government invested $1.6 billion in the Maryland company to support development of the shots. Even with the influx of cash, the challenges to scale up were enormous.
“The messenger RNA vaccines are truly remarkable. They are a great gift to humanity, and they were the first to cross the finish line. But whether or not they will turn out to be the optimal vaccine for these viruses is not clear,” said H. Cody Meissner, a pediatric infectious-diseases specialist at Tufts University School of Medicine. “I don’t think we want to rest on what we have at this point because there’s always an opportunity to improve a vaccine.”