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Omicron Reduces COVID Antibody Protection, Evades Vaccine Shield, Reveals New Study

"There is a very large drop in neutralisation of Omicron by BNT162b2 [Pfizer/BioNTech] immunity relative to the ancestral virus" reveals new South African study



Omicron variant of concern B.1.1.529 of the novel coronavirus can partially evade the protection from BioNTech- Pfizer BNT162b2 vaccine, a research head of a laboratory at Africa Health Research Institute in South Africa said on Twitter. Although people who recovered a previous infection and developed antibodies, and then later got vaccinated are likely to be somewhat protected, researchers in South Africa say.

The Omicron variant significantly reduces the antibodies generated by Pfizer and BioNTech’s vaccine, but not completely as people that have had a COVID-19 infection previously, and received a booster shot may still have protection from severe COVID-19 disease, according to a preliminary study done by the South African scientists released Tuesday, Dec. 7.

'Very large drop' in neutralisation of Omicron by vaccine

There was a 41-fold drop in the ability of the antibodies to neutralize the Omicron variant compared with the original SARS-CoV-2. There was also a significant drop in the protection provided by the vaccines compared with the ancestral strain as well as other variants of the coronavirus. As per the preprint of the study that hasn’t yet been peer-reviewed, the Omicron strain was found to be much better at evading vaccine protection. The Vaccine-induced antibodies were reduced threefold in their ability while earlier they neutralized the previous variants. Researchers noted that some of the variants such as Beta that also dominated in South Africa evade immune protection but Omicron’s evasive ability was far more concerning. 

"The results we present herewith Omicron show much more extensive escape," South African scientists wrote in the study submitted on an online preprint site.

"There is a very large drop in neutralization of Omicron by BNT162b2 [Pfizer/BioNTech] immunity relative to ancestral virus," Sigal said on Twitter. “Omicron escape from BNT162b2 neutralization is incomplete. Previous infection + vaccination still neutralizes," he added.

Previous infection, plus booster likely to increase neutralization level 

Prof. Alex Sigal with the Africa Health Research Institute and a team of scientists studies the human lung cells and blood samples of 12 participants who were vaccinated with the Pfizer/BioNTech vaccine. They then researched how well the antibodies generated by the vaccine neutralized the new Omicron variant. South African scientists researched a total of 14 plasma samples from 12 vaccinated people, of those, 6 were previously infected with COVID-19 and had recovered, developing the antibodies against the SARS-CoV-2. Omicron evaded the immune protection built by the vaccine, but those who recovered COVID-19 infection and got vaccinated were partially protected.

"Previous infection, followed by vaccination or booster, is likely to increase the neutralization level and likely confer protection from severe disease in Omicron infection," Sigal's team concluded.

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