- The Food and Drug Administration should clear Novavax's COVID-19 vaccine for emergency use, a panel of expert advisers indicated Tuesday, voting 21-0, with one abstention, in support of a shot based on older technology that health officials believe could overcome persistent public hesistancy around vaccination.
- As with Pfizer's and Moderna's vaccines, some people who received Novavax's shot in clinical testing developed a type of heart inflammation, although they all recovered. The cardiovascular side effect, which primarily affected young adults, concerned FDA scientists who presented the agency's view at Tuesday's meeting.
- The principal data Novavax mustered in support of its vaccine is also a year old, raising questions about how well the shot might perform against omicron and related subvariants. Company executives emphasized the broad efficacy of their vaccine, which was 90% effective in preventing COVID-19 from a variety of variants that were circulating at the time of the trial.
Nearly 89% of U.S. adults older than 18 years have received at least one dose of a COVID-19 vaccine, although the percentage of people who have completed a two-dose primary series or received a booster dose is substantially lower, according to data the Centers for Disease Control and Prevention presented to the FDA's advisory committee.
Because Pfizer's and Moderna's vaccines rely on newer technology to stimulate an immune response, public health officials believe some people may favor a more traditionally made shot due to concerns over unknown or unreported safety risks.
Novavax's vaccine is a synthetic protein paired with a chemical that's designed to increase the immune response. These types of vaccines have been around for nearly four decades, first in a shot for hepatitis B, and since in vaccines for conditions like human papillomavirus infections and shingles. In the case of COVID-19, Novavax has manufactured a version of the SARS-CoV-2 virus' signature "spike" protein to train the body's immune defenses.
The vaccine secured an emergency listing from the World Health Organization in December, and is authorized for use in the European Union, the U.K., Japan, Australia, New Zealand and Canada.
Novavax has committed to delivering 2 billion doses, including 1.1 billion to non-governmental organizations around the world and 110 million to the U.S. government. Novavax gained funding through Operation Warp Speed, the Trump administration's 2020 push to accelerate to market COVID-19 vaccines, treatments and diagnostics.
Among experts Tuesday, the safety profile of the shot was a particular point of contention, however. Novavax insisted that cases of heart inflammation, which occurred rarely in the trial, were evenly distributed between people who received the vaccine and those who initially received a placebo. (All patients in the trial eventually were vaccinated as part of its design.) FDA expert advisers, meanwhile, were concerned that such heart inflammation, called myocarditis, might be a class effect of all COVID-19 vaccines.
The advisers' vote is non-binding and the FDA can choose to go in another direction, although it usually doesn't. If the FDA decides to authorize the vaccine, it could including a warning as it has with Pfizer's and Moderna's vaccines, although officials cautioned more data might be necessary to justify that.
"The extent of evidence for myocarditis being causally related to this vaccine is not at the same level as for mRNA vaccines," said Doran Fink, the deputy director of the FDA's vaccines office, on Tuesday.
Advisers were also concerned about how well the shot would fare versus omicron, which didn’t appear until after Novavax completed its Phase 3 trial. “It is disappointing that we don't have more updated information because we're measuring efficacy against strains that don't exist any longer,” said Eric Rubin, an adjunct professor at the Harvard School of Public Health and editor in chief of the New England Journal of Medicine.
Novavax’s chief medical officer, Filip Dubovsky, pointed to laboratory tests that indicated the vaccine induced an immune response to omicron, as well as to its effectiveness against variants that were previously circulating. “What we do know from the data that we’ve shown you is that the vaccine works well against the variants that were circulating, and there were quite a number of them,” he said.
Panelists were supportive of the idea that another vaccine is still needed as the pandemic endures. “The mRNA vaccines are truly remarkable," said Cody Meissner, director of pediatric infectious diseases at Tufts University medical school. "But whether or not they end up being the optimal vaccine for this virus is not clear."
Yet others questioned whether a new shot would meaningfully push vaccination rates higher, at least in the U.S.
"I'm friends with a number of vaccine hesitant people, and their hesitancy is more ideological than technological," said Jay Portnoy, a professor of pediatrics at Children’s Mercy Hospital in Kansas City.