South African coronavirus variant may lower vaccine efficacy, ‘escapes’ plasma therapy: scientists
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Concerning preliminary findings on Wednesday add to growing evidence that a coronavirus variant first identified in South Africa escapes the neutralization power by antibodies in convalescent plasma.
Findings were posted ahead of peer review on the bioRxiv site by several universities in South Africa and the National Institute for Communicable Diseases (NICD) of the National Health Laboratory Service.
The 501Y.V2 variant involves nine mutations on the virus’ spike protein, which the virus uses to infect cells. This worries scientists because recently developed vaccines and therapeutics target the proteins, raising worries that changes could impact the efficacy of treatments and vaccines. Scientists believe the recently approved vaccines remain effective against the U.K. variant, although research on the variant first identified in South Africa may have is ongoing.
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Earlier this week, researchers said the South African strain was 50% more infectious, and it has been detected in over 20 countries since late December, the World Health Organization says, Reuters reported. No cases of the strain have been reported in the U.S., though this is potentially due to under surveillance.
Convalescent plasma with antibodies from recovered coronavirus patients is infused to ill patients to battle infection, and the treatment already has emergency authorization in the U.S. Though it may provide benefits to those fighting the virus, the evidence has been inconclusive as to how it works or how best to administer it.
In the preliminary findings posted Wednesday, researchers said the mutated strain nearly dodged, if not obviated, protection offered by the plasma treatment.
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“This lineage exhibits complete escape from three classes of therapeutically relevant monoclonal antibodies,” reads the findings. “Furthermore 501Y.V2 shows substantial or complete escape from neutralizing antibodies in COVID-19 convalescent plasma.”
Researchers said the data emphasize the risk of re-infection, “and may foreshadow reduced efficacy of current spike-based vaccines.” The team tested convalescent plasma from coronavirus patients against the 501Y.V2 strain, and 48% of 44 samples “had no detectable neutralization activity,” study authors wrote.
“These data also have implications for the effectiveness of SARS-CoV-2 vaccines, which are principally based on immune responses to the spike protein,” reads the paper, urgently calling for “rapidly adaptable vaccine design platforms, and the need to identify less mutable viral targets for incorporation into future immunogens.”
Separate research out Tuesday also suggested mRNA vaccines (like those developed by Pfizer and Moderna) may require updates to maintain effectiveness against new strains.
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Pfizer previously told Fox News that the company, along with BioNTech, selected an mRNA platform for its now-authorized vaccine due to flexibility afforded by the technology. “This flexibility includes the ability to alter the RNA sequence in the vaccine to cover new strains of the virus, if one ever were to emerge that is not well covered by the current vaccine,” reads an emailed statement.
In the findings posted Tuesday, a team including scientists from Rockefeller University took blood samples from 20 volunteers who received the vaccines developed by Pfizer and Moderna, and tested their antibodies against various virus mutations in the lab.
With some, the antibodies didn’t work as well against the virus — activity was one-to-threefold less, depending on the mutation, said the study leader, Rockefeller’s Dr. Michel Nussenzweig.
“It’s a small difference but it is definitely a difference,” he said. The antibody response is “not as good” at blocking the virus.
“We don’t want people thinking that the current vaccine is already outdated. That’s absolutely not true,” E. John Wherry, an immunology expert at the University of Pennsylvania, told the Associated Press. “There’s still immunity here … a good level of protection,” but the mutations “do in fact reduce how well our immune response is recognizing the virus.”
Meanwhile, Pfizer and BioNTech published a new study that provides more evidence their COVID-19 vaccine is effective against the UK variant that is believed to be more contagious.
The study, which was published on preprint server bioRxiv and is yet to undergo peer review, analyzed blood samples from eight people in the 18-55 age range and eight people in the 56-85 age range.
The researchers found that the Pfizer vaccine provided “no biologically significant difference in neutralization activity against” the original COVID-19 strain and the UK variant.
While it is good news, researchers wrote, “The ongoing evolution of SARS-CoV-2 necessitates continuous monitoring of the significance of changes for maintained protection by currently authorized vaccines.”
Fox News has requested comment from Pfizer on the Rockefeller researchers’ findings.
The Associated Press and Fox News’ Paul Best contributed to this report.
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