NEW YORK • Pfizer and BioNTech's Covid-19 vaccine appeared to lose only a small bit of effectiveness against an engineered virus with three key mutations from the new variant found in South Africa.

A study by Pfizer and scientists from the University of Texas Medical Branch (UTMB), yet to be peer-reviewed, showed a less than twofold reduction in antibody titer levels, indicating the vaccine would likely still be effective in neutralising a virus with the so-called E484K and N501Y mutations found in the South African variant.

The scientists are engineering a virus with the full set of mutations and expect to have results from that in about two weeks, said UTMB's Professor Shi Pei-Yong, an author of the study.

The results are more encouraging than another non-peer-reviewed study from Columbia University earlier on Wednesday which used a slightly different method and showed antibodies generated by the shots were significantly less effective against the South African variant.

A possible reason for the difference is that the Pfizer findings are based on an engineered coronavirus, and the Columbia study used a pseudovirus based on the vesicular stomatitis virus, a different type of virus, Prof Shi said. He believes that the finding in pseudoviruses should be validated using the real virus.

The study also showed even better results against several key mutations from the highly transmissible UK variant of the virus. Prof Shi said they were working on an engineered virus with the full set of mutations from that variant.

REUTERS