Novavax’s updated protein-based COVID-19 vaccine has finally won authorization from the Food and Drug Administration, a late-coming achievement that provides Americans with their only alternative to mRNA-based shots for the fall booster campaign now underway.
While the FDA’s authorization was announced Tuesday afternoon, the Centers for Disease Control and Prevention has already signed off on recommending the shot. Its September 12 recommendation that all Americans ages 6 months and up get an updated COVID-19 vaccine was a blanket recommendation for any updated shots authorized or approved by the FDA, which now includes Novavax. The vaccine will be available to everyone ages 12 and up.
The Novavax vaccine uses a traditional protein subunit-based design; it directly introduces the SARS-CoV-2 spike protein to our cells along with an established adjuvant that enhances immune responses. The spike protein is a key outer protein the virus uses to enter human cells. The mRNA vaccines, by contrast, are a newer design that introduces the genetic code for the spike protein, which the cells then translate into protein on their own. In either case, with a disembodied spike protein, the immune system gets a chance to identify and train defensive responses against the pandemic pathogen before a live SARS-CoV-2 virus comes knocking.
Like the mRNA vaccines, Novavax’s updated vaccine for the 2023–2024 season is a monovalent shot designed to target the spike protein of the recent omicron subvariant, XBB.1.5.
Head-to-head clinical data does not indicate if this updated Novavax vaccine will offer more or less protection against the latest circulating variants this season, particularly in a population with varying degrees of pre-existing immune protection from differing prior vaccinations and infections. But accumulated efficacy data suggests it’s similarly effective to the mRNA shots. In a 2021 study involving more than 29,000 participants, the original formulation of the vaccine had an overall efficacy estimate of 90.4 percent against symptomatic COVID-19.
Nonclinical data on the 2023–2024 updated version found that it produced immune responses against currently circulating omicron subvariants, including XBB.1.5, XBB.1.16, and XBB.2.3. It induced neutralizing antibody responses to newly emerging subvariants BA.2.86, EG.5.1, FL.1.5.1, and XBB.1.16.6, Novavax said. The company also has data showing T-cell responses against subvariants EG.5.1 and XBB.1.16.6.
The safety data for the vaccine is similar to the mRNA vaccines, with the common side effects being headache, nausea or vomiting, muscle pain, joint pain, injection site tenderness, injection site pain, fatigue, and malaise.
In a statement Tuesday, the FDA’s top vaccine regulator, Peter Marks, said that the authorization of Novavax’s updated vaccine “provides an additional COVID-19 vaccine option that meets the FDA’s standards for safety, effectiveness, and manufacturing quality needed to support emergency use authorization. As we head into the fall season and transition into 2024, we strongly encourage those who are eligible to consider receiving an updated COVID-19 vaccine to provide better protection against currently circulating variants.”
Novavax’s CEO John Jacobs made a similar statement Tuesday, saying the authorization “means people will now have the choice of a protein-based non-MRNA option to help protect themselves against COVID-19, which is now the fourth leading cause of death in the US. In the coming days, individuals in the US can go to pharmacies, physicians’ offices, clinics, and various government entities to receive an updated Novavax vaccine.”
The company added that it expects its vaccines to be available in thousands of locations nationwide, including big pharmacies like CVS Pharmacy and Rite Aid.
There were hopes that Novavax’s updated vaccine would be available alongside the two mRNA vaccines (from Moderna and Pfizer-BioNTech), which have already rolled out nationwide, albeit with many bumps. It’s unclear what caused the delay, but Novavax, a Maryland-based company, has struggled throughout the pandemic with getting its manufacturing up and running. The protein-based vaccine is also more difficult to tweak and takes longer to manufacture than the mRNA vaccines—a drawback of the traditional design.
Still, the company hopes the old-school alternative to the newer mRNA vaccines will sway some vaccine holdouts. Previously, the FDA and CDC had reserved Novavax vaccines for those who refused mRNA vaccines. But the updated vaccine will be available to everyone ages 12 and up, allowing for more mix-and-match vaccination for those interested.