In its new report, the New England Journal of Medicine has said that the South African variant of the coronavirus may reduce antibody protection from the Pfizer vaccine by two-thirds.

The study released on Wednesday, showed reduced neutralization of the South Africa-like virus by blood from people who had been immunized with the Pfizer-BioNTech vaccine. Researchers at Pfizer and the University of Texas Medical Branch said that while the blood serum samples produced less neutralizing antibody activity, it was still enough to neutralize the virus, CNN reported.

However, since there is no established benchmark yet to determine what level of antibodies are needed to protect against the virus, it is unclear whether the two-thirds reduction will render the vaccine ineffective against the new variant.

Pfizer and BioNTech in a statement said that there is no real-world evidence that the South African variant can elude their shot. However, they said they are getting ready to develop an updated vaccine or booster if need be.

They further said that they are also testing whether the vaccine works against a variant that has emerged in Brazil, as well as against other mutant strains.