What would a Novavax Covid-19 vaccine mean in the United States?

A committee of independent and expert advisors for the Food and Drug Administration voted overwhelmingly to authorize the two-dose Novavax Covid-19 vaccine yesterday, with 21 of 22 committee members voting in favor of the vaccine and one member abstaining.

Approval is only for a two-dose primary series in adults, not for boosters. The FDA is not obligated to follow the advice of its committee – the Advisory Committee on Vaccines and Related Biologicals (VRBPAC) – but the agency generally heeds his advice. If the FDA clears the vaccine, the Centers for Disease Control and Prevention will need to approve its use before it becomes available.

The decision about the Novavax vaccine, which is already licensed in dozens of other countries, is not straightforward in the United States. The vaccine has some advantages over currently approved vaccines, but has several knocks against it.

Traditional design

In terms of design, the vaccine follows a more traditional recipe than the two mRNA-based Covid-19 vaccines or Johnson & Johnson’s adenovirus vector-based design. Both of these designs are relatively new and work by delivering the genetic code for the SARS-CoV-2 spike protein to our cells, which then translate the code. The Novavax vaccine, on the other hand, is a protein subunit vaccine that directly delivers the SARS-CoV-2 spike protein to cells, as well as an adjuvant, which is an additive used in vaccines to enhance immune responses to the vaccine. In this case, the adjuvant is derived from saponin compounds found in the Chilean soap tree, which have previously been used in FDA-approved vaccines.

Typically, the protein subunit vaccine design is proven and approved; it is already used in vaccines against influenza, whooping cough (whooping cough) and meningococcal infection, for example.

Who would get it?

Novavax leaned heavily on the traditional design in its submission to the FDA. Now that we are more than two years into the pandemic and mRNA vaccines are readily available in the United States, most people who want to get vaccinated have already been vaccinated. This raises a key question about what role Novavax’s vaccine still has to play and how it warrants “emergency use” authorization given the availability of other vaccines.

The company has firmly targeted its traditional injections at vaccine holders, which the CDC estimates at around 27 million. They may be wary of more innovative mRNA vaccines, but could ultimately be swayed to get vaccinated if offered an alternative perceived as more conventional, Novavax argued.

“Millions of Americans today are still unvaccinated,” said Greg Poland, director of the Mayo Vaccine Research Group, who spoke on behalf of the Novavax vaccine at yesterday’s meeting. “For people who aren’t fully vaccinated and are waiting for another option, having a vaccine platform that multiple stakeholders, including regulators, doctors, and the public know about can help alleviate some of the challenges we face today.

Although some committee members were skeptical about the influence of another option, the FDA’s top vaccine regulator, Peter Marks, appeared to buy it. “We have a vaccination problem that is very serious in the United States, and anything we can do to make people more comfortable about being able to accept these potentially life-saving medical products is something we feel compelled to do. TO DO. “, Marc said. He also noted that some Americans are unable to obtain mRNA vaccines due to adverse reactions, so the protein-based vaccine would be a welcome new option.

Efficiency, variants and safety

Novavax’s vaccine had strong estimates of efficacy in a clinical trial published in February in The New England Journal of Medicine. In the trial of more than 29,000 participants, the vaccine had an estimated 90.4% overall efficacy against symptomatic Covid-19. Vaccine safety data suggests that it is generally safe and well tolerated, although there may be a link to rare cases of heart inflammation (myocarditis) seen with mRNA vaccines.

That said, the trial ended last year before the arrival of Delta and Omicron (with all its sub-variants). It is unclear how the efficacy of the vaccine will hold up against these new variants.

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