The Omicron variant of the coronavirus can partially evade the protection from two doses of Pfizer and partner BioNTech’s COVID-19 vaccine, the research head of a laboratory at the Africa Health Research Institute in South Africa said on Wednesday.
Still, the study showed that blood from people who had received two doses of the vaccine and had a prior infection were mostly able to neutralize the variant, suggesting that booster doses of the vaccine could help to fend off infection.
Alex Sigal, a professor at the Africa Health Research Institute, said on Twitter there was “a very large drop” in neutralization of the Omicron variant relative to an earlier strain of COVID-19.
The lab tested blood from 12 people who had been vaccinated with two doses of the Pfizer/BioNTech vaccine, according to a manuscript posted on the website for his lab. The preliminary data in the manuscript has not yet been peer reviewed.
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 said.
“These results are better than I expected. The more antibodies you got, the more chance you’ll be protected from Omicron,” Sigal said on Twitter.
He said the lab had not tested the variant against blood from people who had received a booster dose, because they are not available in South Africa yet.
According to the manuscript, the lab observed a 41-fold decline in levels of neutralizing antibodies against the Omicron variant.
Sigal said on Twitter that figure is likely to be adjusted after his lab does more experiments.
