Newly emerged variants of the novel coronavirus have sparked a key question: Will existing COVID-19 vaccines be less effective against them? But scientists have preliminary data showing that may not be the case, at least for Pfizer and BioNTech’s shot.
Researchers from the University of Texas and Pfizer found that, in lab dishes, the vaccine was able to neutralize an engineered version of a variant, which bears an N501Y mutation in its spike protein. The finding was published in bioRxiv and hasn’t been peer-reviewed.
Variants of coronavirus with this mutation were first discovered in the U.K. and South Africa and immediately grabbed global attention because they are more contagious.
Currently available COVID vaccines—including Pfizer and BioNTech’s Comirnaty, or BNT162b2—target the spike protein of SARS-CoV-2, the coronavirus behind COVID-19. The N501Y mutation improves the ability of the virus’ spike protein to bind to its receptor on human cells, making it easier to gain entry for infection.
To test whether Comirnaty worked against the mutation, the scientists collected antibodies from 20 vaccinated trial participants and compared their ability to kill off the engineered virus with the N501Y mutation to their ability to neutralize the strain on which Pfizer and BioNTech based Comirnaty.
The antibodies cleared the virus at similar concentrations, indicating no reduction in neutralization activity, the researchers said.
BioNTech CEO Ugur Sahin previously predicted that Comirnaty would “highly likely” work against the variant—and even if studies proved otherwise, the company would be able to turn around a new vaccine candidate based on the variant in six weeks, he said during a press conference on Dec. 22.
Previously, Comirnaty—which is designed to trigger different types of antibodies to attack the virus—showed it was 95% effective in preventing COVID-19.
While the latest study lends scientific evidence to backing Sahin’s confidence, there are other concerning mutations beside N501Y. For example, the new SARS-CoV-2 variant found in South Africa also bears the E484K mutation in the spike protein.
Based on antibodies taken from people previously infected with SARS-CoV-2, scientists at Fred Hutch Cancer Research Center recently pointed out that that mutation may trigger “greatly reduced susceptibility to neutralization” by some people's antibodies.
In a statement Friday, Pfizer and BioNTech stressed that further data are needed to determine their vaccine’s effectiveness in new virus variants but expressed confidence that they could make any necessary tweaks.
“If the virus mutates such that an update to the vaccine is required to continue to confer protection against COVID-19, we believe that the flexibility of BioNTech’s proprietary mRNA vaccine platform is well suited to enable an adjustment to the vaccine,” they said.