Recent studies suggest that even two doses of Pfizer-BioNTech COVID-19 vaccine do not guarantee complete protection from the Omicron variant that was detected in South Africa last month.
Alex Sigal, the research head of a laboratory at the Africa Health Research Institute in South Africa, announced this on Twitter on Tuesday.
He said that most of the patients who got two doses of vaccine after getting infected neutralized the variant, indicating that the booster doses might help fend off infection.
He listed a few of the observations from the study on his Twitter.
“Omicron still uses ACE2. There is a very large drop in the neutralization of Omicron by BNT162b2 immunity relative to an earlier strain of COVID-19,” Sigal said in a series of tweets.
We have completed our first experiments on neutralization of Omicron by Pfizer BNT162b2 vaccination elicited immunity
Manuscript available at https://t.co/rGaEB9GdmS
and should be available on medRxiv in the coming days
— Alex Sigal (@sigallab) December 7, 2021
On his website, the link of which was shared in the tweets, the professor said that his lab tested blood samples of 12 patients who had been fully inoculated with the Pfizer-BioNTech vaccine.
“Blood from five out of six people who had been vaccinated as well as previously infected with COVID-19 still neutralized the Omicron variant,” the manuscript on his website said.
“These results are better than I expected. The more antibodies you got, the more [higher] chance you’ll be protected from Omicron,” it added.
The professor also said that the lab had not yet tested the blood samples of people who had received a booster dose, as they were not available in the country yet.
According to the manuscript, the lab observed a 41-fold decline in levels of neutralizing antibodies against the Omicron variant.
The professor, however, mentioned that the data posted on his website is raw and “has not been corrected for values going below the lowest dilution used.”
“We present the raw fold change, which is likely to be adjusted as we do more experiments.”
Sigal said that there was not enough data to prove that the Pfizer shots were “less able to prevent severe illness or death.”
Last week, BioNTech CEO, Ugur Sahin, said, “We think it’s likely that people will have substantial protection against severe disease caused by Omicron.”
The Omicron variant has globally triggered alarms of another surge in infections. The virus has reached more than two dozen countries, including the United States, in less than two weeks of being first detected.
