Response comparable to mRNA vaccines and if authorized, could help bolster global vaccine supplies

SEATTLE (June 27, 2022) – A new analysis of the Novavax PREVENT-19 clinical trial, conducted by researchers with the COVID-19 Prevention Network (CoVPN), concluded that this recombinant protein vaccine produced an antibody response comparable to mRNA vaccines and, if authorized, could help bolster global vaccine supplies.

As previously reported, the clinical trial found that two doses of the Novavax vaccine were 90 percent effective at preventing symptomatic COVID-19 among almost 30,000 randomized participants between December 27, 2020 and February 18, 2021.

The CoVPN analysis, posted on medRxiv but not yet peer-reviewed, showed that the Novavax vaccine produced the same antibody markers as mRNA vaccines and they performed well as “correlates of protection,” says Peter Gilbert, PhD, corresponding author of the study and a biostatistician at Fred Hutchinson Cancer Center, where CoVPN is headquartered.

MRNA vaccines inject a messenger that instructs cells to produce the viral spike protein, inducing the immune system to produce antibodies to attack it. Recombinant protein vaccines, by contrast, inject a replica of the spike protein to prompt the immune system to recognize it as foreign, and an adjuvant to enhance the immune response to produce antibodies against it.  Neither of the injectables can cause COVID-19.

“This is the first study to directly support antibody correlates of protection for a recombinant protein COVID-19 vaccine,” Dr. Gilbert explains. “That’s an important finding because this traditional technology has long been used for mass vaccination against flu and other pathogens. Deploying this vaccine and other recombinant protein vaccines against COVID-19 could help us better meet the large global demand.”

Correlates of protection define the immune response a vaccine or natural viral infection would need to trigger so that an individual is protected from a virus or infectious disease in the future. A correlate of protection is an immune marker measuring the concentration or what Gilbert refers to as the “killing power” of antibodies against the SARS-CoV-2 spike protein in a vaccinated person’s blood sample. It can be used to reliably predict -- and quantify -- how well the vaccine protects against COVID-19.

Previous vaccine trials conducted by CoVPN and its collaborators at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, and the Biomedical Advanced Research and Development Authority (BARDA), as well as others, demonstrated the power of antibody markers in Moderna’s mRNA and Johnson & Johnson’s Ad26 vaccines.

Now, the same has been shown for Novavax’s COVID-19 vaccine candidate, and Gilbert and colleagues believe it could have a profound impact on the supply of future vaccines and boosters. An FDA advisory committee voted 21-0 on June 7 to recommend that FDA authorize the vaccine, but it is still under review. Outside the U.S., Novavax’s COVID vaccine has an emergency-use listing by the World Health Organization, is conditionally authorized by the European Commission and has approval or emergency-use authorization in more than 40 countries.

Gilbert notes that an FDA advisory meeting on June 28 will discuss recommendations about potential vaccine strain changes for new vaccines to be deployed in the fall, when another COVID surge is expected.

With fall just around the corner, vaccine manufacturers could be challenged to make enough vaccines to meet national and global supply needs, he points out. Adding new options from manufacturers of recombinant protein vaccines could help prevent potential shortages.

Currently approved COVID vaccines use the original ancestral strain, and their protection level has diminished over time as variants have emerged that are increasingly able to evade vaccine antibodies, Gilbert explains.

“These new correlates results provide important context for the upcoming FDA discussion, as they support use of an antibody marker for guiding strain-selection decisions for recombinant protein vaccines to bolster the supply of COVID vaccines,” he says.

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