SILVER SPRING, Md. — A Food and Drug Administration advisory committee voted 21-0, with one abstention, Tuesday to recommend emergency authorization of Novavax’s COVID-19 vaccine for adults, moving the United States closer to adding a protein-based vaccine to a program now dominated by mRNA products.

The vote is advisory and does not itself authorize the vaccine. The FDA’s Vaccines and Related Biological Products Advisory Committee met in open session to consider whether the known and potential benefits of NVX-CoV2373 outweigh its known and potential risks for people 18 and older. FDA officials must still complete their review before any emergency use authorization can take effect.

A different vaccine platform could broaden the U.S. portfolio

Novavax’s vaccine uses recombinant technology to produce copies of the SARS-CoV-2 spike protein and combines that antigen with the company’s Matrix-M adjuvant to strengthen the immune response. The approach differs from the messenger-RNA technology used by Pfizer-BioNTech and Moderna and from the viral-vector technology used by Johnson & Johnson.

Novavax said after the meeting that the committee’s 21-0 recommendation could make its product the first protein-based COVID-19 vaccine available in the United States if FDA grants authorization. The proposed regimen is two 0.5-milliliter intramuscular doses given 21 days apart, and the vaccine can be stored at standard refrigerator temperatures of 2 to 8 degrees Celsius.

That storage profile and more familiar vaccine platform are potentially important operational advantages. Federal officials and clinicians have long hoped an additional option could appeal to some adults who have declined mRNA vaccination or simplify distribution in settings without ultra-cold storage infrastructure.

PREVENT-19 showed 90.4% efficacy before Omicron emerged

The central efficacy evidence comes from PREVENT-19, a Phase 3 randomized trial involving nearly 30,000 adults at 119 sites in the United States and Mexico. The published New England Journal of Medicine results found 77 symptomatic COVID-19 cases during the primary analysis period: 14 among vaccine recipients and 63 among placebo recipients, corresponding to vaccine efficacy of 90.4%.

Ten moderate cases and four severe cases occurred in the placebo group, with none in the vaccine group during that analysis. Most sequenced infections were variants of concern or interest circulating at the time, particularly Alpha. The study was conducted before Omicron became dominant, so the 90.4% figure should not be interpreted as a direct measure of protection against today’s circulating variants.

The National Institutes of Health, which supported the trial through the COVID-19 Prevention Network, reported in its June 2021 trial summary that the vaccine was generally well tolerated and showed 100% protection against moderate and severe disease in the initial analysis. Common reactions included injection-site pain or tenderness, fatigue, headache and muscle pain.

The committee weighed a myocarditis signal alongside the benefits

The advisory review was not simply a confirmation of efficacy. FDA staff and committee members examined reports of myocarditis and pericarditis — inflammatory heart conditions that have also been associated rarely with mRNA COVID-19 vaccines — among Novavax trial participants. The number of cases was small, making it difficult to determine the precise relationship to vaccination, but the signal became an explicit part of the benefit-risk discussion.

Novavax argued that overall myocarditis rates in its controlled trial were balanced between vaccine and placebo groups and that the available data did not establish a causal relationship. The committee nevertheless had to consider whether the pattern warranted warning language, additional monitoring or other conditions if the vaccine is authorized.

That scrutiny reflects the regulatory context in which the product is arriving. The United States already has effective vaccines, so a new entrant must demonstrate not only that it can prevent disease but also that its safety profile and potential public-health value justify adding another option. The committee’s near-unanimous vote indicates that members believed the balance favored authorization for adults, while leaving final labeling and risk-management decisions to FDA.

The U.S. review has taken months because manufacturing is part of the authorization

Novavax submitted its U.S. EUA request on January 31, later than the company had initially hoped as it worked through manufacturing and regulatory requirements across a global production network. In May, the company announced that FDA had formally scheduled the June 7 advisory review and emphasized that the vaccine remained unauthorized in the United States.

Manufacturing review is particularly important for a biologic product because regulators must establish that commercial vaccine made at approved sites is consistently comparable to the material evaluated in clinical trials. Novavax said this week that it had submitted updated manufacturing information to FDA and would continue working with the agency as the review proceeds.

The vaccine is already authorized in more than 40 countries, according to the company, and has received World Health Organization emergency-use listing. WHO added Nuvaxovid to its list in December 2021, describing the protein-based product as another tool for expanding global vaccine supply.

An authorization would add choice, but uptake remains uncertain

By mid-2022, most U.S. adults who wanted COVID-19 vaccination have already had access to multiple products for well over a year. That means Novavax would enter a very different market from the one Pfizer, Moderna and Johnson & Johnson faced during the first vaccination campaign. Its value may lie less in accelerating mass rollout than in reaching specific people who prefer a non-mRNA platform, supporting booster strategies if authorized for those uses later, and diversifying supply.

For now, however, the committee considered only the request for a two-dose primary series in adults. The advisory vote does not authorize boosters, pediatric use or an Omicron-specific formulation, and it does not mean the product can immediately be shipped for routine U.S. administration.

The next decision belongs to FDA. If the agency concludes that the clinical, safety and manufacturing evidence satisfies the emergency-use standard, Novavax would then move to the Centers for Disease Control and Prevention for recommendations on how the vaccine should be used in practice. Until those steps occur, Tuesday’s 21-0 vote is best understood as a significant regulatory milestone rather than the final approval of a new vaccine.