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Omicron Dramatically Reduces Protection of Covid Antibodies in Small Study of Pfizer Vaccine Recipients


Nurse Mary Ezzat administers a Pfizer COVID-19 booster to Jessica M. at UCI Medical Center in Orange, Calif. On Thursday, August 19, 2021.

Jeff Gritchen | MediaNews Group | Orange County Register via Getty Images

South African scientists say the omicron Covid variant significantly reduces the antibodies generated by Pfizer and BioNTech’s vaccine, although people who have recovered from the virus and received a booster will likely have more protection against serious illnesses, according to a small preliminary study published on Tuesday.

Professor Alex Sigal of the Africa Health Research Institute and a team of scientists tested blood samples from 12 people who had previously been vaccinated with the Pfizer / BioNTech vaccine, specifically looking at how well the antibodies generated by the vaccine can neutralize the new variant – which means blocking its ability to infect cells.

They found a 41-fold decrease in the ability of their antibodies to neutralize the omicron variant compared to the original virus, a dramatic reduction in its performance against the original ancestral strain as well as other variants, according to a prepublication. from the study that has not yet been peer reviewed. Antibodies induced by the vaccine decreased by three times their ability to neutralize the previous beta variant that previously dominated South Africa, suggesting that omicron is much better at evading protection.

“The results we present here with Omicron show much more extensive breakout” than the beta variant, the researchers wrote. “A previous infection, followed by vaccination or a booster is likely to increase the level of neutralization and possibly to confer protection against serious illness in Omicron infection.”

The preprint study has not yet been peer reviewed and it tested 14 plasma samples from 12 vaccinated people, 6 of whom had previously been infected. Scientists made their research on Covid available before going through the extensive peer review process due to the urgency of the pandemic.

Pfizer CEO Albert Bourla said earlier Friday that the company could develop a vaccine specifically targeting omicron by March 2022 if needed. Bourla said it would take a few weeks to get more definitive data on whether current vaccines provide sufficient protection against the variant.

The CEO of Pfizer previously told CNBC that the protection provided by the company’s two-dose vaccine would likely decline in part in the face of omicron.

South African scientists also found that omicron binds to the same receptor, known as ACE2, to infect human lung cells that previous variants used.

This is a developing story. Please check for updates.


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