For the study, researchers from Pfizer and the University of Texas Medical Branch developed genetically engineered versions of the virus to carry some of the mutations found in B.1.351. They tested them with blood samples from 15 people who had received two doses of the Pfizer / BioNTech vaccine as part of a clinical trial.
Although the blood serum samples produced less neutralizing antibody activity, it was still enough to neutralize the virus, they wrote in a letter to the journal. This is in line with other studies. And it falls well within what is seen with other viruses, one of the researchers said.
“Although we do not yet know exactly what level of neutralization is needed to protect against COVID-19 disease or infection, our experience with other vaccines tells us that the Pfizer vaccine is likely to provide relatively good protection against this new variant,” said Scott. Weaver, director of the Institute for Human Infections and Immunity at the University of Texas Medical Branch and an author of the study, told CNN.
“The decrease of about 2/3 in neutralization levels against the South African variant is quite small compared to variations in neutralization levels generated by vaccines against other viruses that have even more variability in their protein sequences than SARS-CoV-2,” Weaver added.
Pfizer said there is no evidence in real life that the variant escapes the protection that the vaccine provides. “Nonetheless, Pfizer and BioNTech are taking the necessary steps, making the right investments, and engaging in the right discussions with regulators to be able to develop and apply for an updated mRNA vaccine or booster as a strain that supports the protection of the vaccine is being identified, ”Pfizer said in a statement.
Separately, a team from the National Institutes of Health and Moderna published a letter in the same journal with the findings of an experiment they reported last month. They also reported a reduction in the antibody response to viruses that were genetically engineered to look like the B.1.351 variant, but not enough to make the vaccine less effective.
“Despite this reduction, neutralizing titer levels with (the variant discovered in South Africa) remain above the levels expected to be protective,” the company said in a statement.
They found no reduction in efficacy against a variant first seen in the UK known as B.1.1.7.