New COVID-19 Variant Defeats Plasma Treatment, MABs, May Reduce Vaccine Efficacy

By Reuters Staff

January 21, 2021

JOHANNESBURG (Reuters) - The new COVID-19 variant identified in South Africa can evade the antibodies that attack it in treatments using blood plasma from previously recovered patients, and may reduce the efficacy of the current line of vaccines, scientists said on Wednesday.

Researchers are racing to establish whether the vaccines currently being rolled out across the globe are effective against the so-called 501Y.V2 variant, identified by South African genomics experts late last year in Nelson Mandela Bay.

"This lineage exhibits complete escape from three classes of therapeutically relevant monoclonal antibodies," the team of scientists from three South African universities working with the National Institute for Communicable Diseases (NICD) wrote in a paper published ahead of peer review on the bioRxiv website (https://bit.ly/2Y0lHEt).

"Furthermore, 501Y.V2 shows substantial or complete escape from neutralising antibodies in COVID-19 convalescent plasma," they wrote, adding that their conclusions "highlight the prospect of reinfection ... and may foreshadow reduced efficacy of current spike-based vaccines."

The 501Y.V2 variant is 50% more infectious than previous ones, South African researchers said this week. It has already spread to at least 20 countries since being reported to the World Health Organisation in late December.

It is one of several new variants discovered in recent months, including others first found in England and Brazil.

The variant is the main driver of South Africa's second wave of COVID-19 infections, which hit a new daily peak above 21,000 cases earlier this month, far above the first wave, before falling to about 12,000 a day.

The paper said it remained to be seen how effective current vaccines were against 501Y.V2, which would only be determined by large-scale clinical trials. But results showed the need for new vaccines to be designed to tackle the evolving threat, it said.

Liam Smeeth of the London School of Hygiene and Tropical Medicine, who was not involved in the study, noted that these were laboratory tests, and it would be unwise to extrapolate the findings to humans at this point.

"The data do raise the possibility that the protection gained from past infection with COVID-19 may be lower for re-infection with the South African variant," he said. "The data also suggest that the existing vaccines could be less effective against the South African variant."

Smeeth called for large studies among populations where the variant is common.

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