a committee independent expert advisor Yesterday, the U.S. Food and Drug Administration voted overwhelmingly to approve two doses of the Novavax Covid-19 vaccine, with 21 of the 22 committee members voting for the vaccine and one member abstaining.
Approval is for the two-dose primary series for adults only, not for boosters. FDA is not obligated to follow the recommendations of its committees— Advisory Committee on Vaccines and Related Biological Products (VRBPAC) – but the agency usually listens to its advice. If the FDA authorizes the vaccine, the Centers for Disease Control and Prevention will need to sign off on it before it becomes available.
The decision on the Novavax vaccine has been authorized in dozens of other countries, but it was not an easy one in the United States. The vaccine has some advantages over currently approved vaccines, but also some challenges against it.
In terms of design, the vaccine follows a more traditional formulation than two mRNA-based Covid-19 vaccines or Johnson & Johnson’s adenoviral vector-based designs. Both designs are relatively new, and they work by passing the genetic code for the SARS-CoV-2 spike protein to our cells, which then translate that code. The Novavax vaccine, on the other hand, is a protein subunit-based vaccine that delivers the SARS-CoV-2 spike protein directly to cells along with adjuvants, which are additives used in vaccines to boost the immune response to vaccines. in this case, adjuvant Derived from saponin compounds found in the saponin tree, which have previously been used in FDA-approved vaccines.
In general, protein subunit vaccine design is tried and trusted; for example, it has been used in vaccines to prevent influenza, whooping cough (whooping cough), and meningococcal infections.
Who will get it?
Novavax leaned heavily toward the traditional design when pitched to the FDA. Now that we’re more than two years into the pandemic, and mRNA vaccines are readily available in the U.S., most people who want to get vaccinated have already been vaccinated. That raises a key question about what else Novavax’s vaccine could do, and how it could warrant an “emergency use” authorization given the availability of other vaccines.
The company has firmly targeted its traditional vaccines at vaccine holders, who the CDC estimates at around 27 million. Novavax thinks they may be wary of more innovative mRNA vaccines, but could end up being vaccinated if offered a supposedly more traditional alternative.
“Millions of Americans are still unvaccinated today,” said Greg Poland, director of the Mayo vaccine research group, who spoke on behalf of Novavax Vaccines at yesterday’s meeting. “For those who are not fully vaccinated and are waiting for an alternative, having a vaccine platform familiar to multiple stakeholders including regulators, physicians and the public can help alleviate some of the challenges we face today. “
While some committee members wondered whether another option would sway opponents, Peter Marks, the FDA’s top regulator of vaccine oversight, appeared to embrace it. “We do have a very serious vaccination problem in the U.S., and anything we can do to make people more comfortable receiving these potentially life-saving medical products is something we think we have to do,” Marks said. He also noted that some Americans cannot get mRNA vaccines due to adverse reactions, so a protein-based vaccine would be a welcome new option.
Efficacy, Variation and Safety
Novavax’s vaccine has solid efficacy estimates in clinical trial published in February New England Journal of Medicine. In trials with more than 29,000 participants, the vaccine’s overall efficacy against symptomatic Covid-19 was estimated at 90.4%. Safety data for the vaccine suggest that it is generally safe and well-tolerated, although it may be associated with rare cases of heart inflammation (myocarditis) seen with the mRNA vaccine.
That said, the trial was completed last year before the Delta and Omicron (and all their sub-variants) appeared. It’s unclear how the vaccine’s efficacy will stand up to these new variants.