Pfizer-BioNTech’s vaccine for COVID-19 appears to work against a key mutation found in two highly contagious strains of the illness whose emergence has caused alarm, according to early findings of a study by the makers of the vaccine.
Pfizer and its German partner, BioNTech, whose US headquarters is located in Cambridge, said Friday that antibodies found in people who received the vaccine appeared to neutralize strains of the virus that recently emerged in the United Kingdom and South Africa and share a key genetic mutation.
The study, which appeared on a pre-print server and has yet to be subjected to peer review, suggest that the mutation in the two variants “does not create resistance to the Pfizer-BioNTech vaccine induced immune responses,” according to a statement from the companies.
The companies and the University of Texas Medical Branch, which helped work on the study, said they were encouraged by the early results but that further research is needed to determine if the vaccine protects people from the two new strains.
Researchers used blood taken from 20 people who were vaccinated in Pfizer-BioNTech’s late-stage clinical study and introduced the two strains containing the key mutation in the laboratory to obtain the early findings.
The Pfizer-BioNTech vaccine was the first one cleared by the Food and Drug Administration for emergency used in the United States last month. A second vaccine made by Cambridge-based Moderna received a similar authorization a week later.
Friday’s findings are encouraging but “somewhat limited,” according to Dr. David Montefiori, a virologist at Duke University.
Montefiori said the British strain has eight mutations on the spike protein — the part of the coronavirus that the pathogen uses to invade a cell — that distinguish it from the dominant virus in the pandemic. The same is true of the South African variant, although they are eight different mutations.
Montefiori said he is studying how effective the Pfizer-BioNTech and Moderna vaccines are against the complete British variant, and South African researchers are doing the same thing with the strain that emerged in their country, he said. He hoped results would be available within weeks.
“The mutation [Pfizer-BioNTech] studied ... is the one scientists were most concerned about because of where it is located on the Spike protein,” he wrote in an e-mail. “However, it is important to get a more definitive answer with the complete variant containing all 8 mutations.”
Jonathan Saltzman can be reached at firstname.lastname@example.org.