Studies have shown that Pfizer-BioNTech and Modern COVID-19 vaccines may have reduced protection against the most contagious variant first discovered in South Africa, raising concerns about the effectiveness of vaccines against the strain.
Reports in the New England Journal of Medicine indicated that the two vaccines currently available in the United States had diminished antibody protection by fighting mutations found in the South African strain, Reuters reported. But both studies showed that vaccines appeared to generate enough antibody response to neutralize the COVID-19 virus.
The studies used genetically engineered types of viruses against blood samples from people who had already been vaccinated, the Washington Post reported.
The Pfizer study determined that by fighting the South African variant about a third of its antibodies were activated compared to when an original strain was fought.
According to Reuters, for the Modern vaccine, researchers found a six-fold decrease in antibody response to the variant first found in South Africa. But the study indicated that the effectiveness of the Modern strain vaccine was not yet known.
It is unclear whether the reduced antibody response will cause vaccines to be ineffective against strain B.1.351, as it is currently unknown what level of neutralization is needed to combat the virus.
Pfizer, in a statement, said the company was “taking the necessary steps … to develop and seek authorization” for an updated or booster vaccine that would help combat the South African variant.