Antibodies in blood collected from 40 people who received both doses of the Pfizer vaccine, 21 days apart, were able to neutralize the B.1.1.7 strain of COVID-19, which was first identified in England in the fall, the researchers said.
The immunity generated against this new strain was similar in efficiency to that against the original Wuhan version of the virus, they said.
The findings suggest that the U.K. strain of the virus is “unlikely” to “escape … protection” offered by the vaccine, according to the researchers.
“Although sustained neutralization of the current B.1.1.7 variant is reassuring, preparation for potential COVID-19 vaccine strain change is prudent,” they wrote.
“Adaptation of the vaccine to a new virus strain would be facilitated by the flexibility of mRNA-based vaccine technology,” they said.
The Pfizer vaccine, which received an emergency use authorization from the U.S. Food and Drug Administration in December, was found to offer 95% protection against earlier strains of COVID-19 during clinical trials.
However, concerns have been raised about the vaccine’s effectiveness against new strains first identified in England, South Africa and Brazil in the fall, which appear to be more contagious and may cause more serious illness.
For this study, the researchers used blood samples from 40 people who had received both doses of the Pfizer vaccine.
As a result of vaccination, the blood contained antibodies, or cells created by the immune system to fight off viruses, against COVID-19, the researchers said.
The researchers tested the ability of the antibodies created by the Pfizer vaccine to fight off both the original Wuhan strain of the virus as well as the newer B.1.1.7 strain.
The blood had “slightly reduced” but largely preserved neutralizing antibodies against the B.1.1.7 strain, the researchers said.