The Ômicron coronavirus variant partially escapes the protection offered by Pfizer’s Covid-19 vaccine, but those who have already been infected and later immunized will likely be well protected, South African researchers reported on Tuesday (7).
Booster doses are also effective in protection, he told the CNN Alex Sigal, from the African Health Research Institute, who led the study team.
It is the first research that directly examines how Ômicron behaves in vaccinated people.
Laboratory tests using samples from 12 people who were fully vaccinated with Pfizer’s vaccine showed that the new variant can escape the immunological protection developed by the immunizer – but not completely.
“There is a very large drop in the neutralization of Ômicron by the vaccine compared to the original strain,” said Sigal. The findings are good news, he told the CNN.
“I found it very positive. I expected worse,” Sigal said in a telephone interview. The mutations that characterize the Omicron variant appeared to allow it to completely escape the immunity offered by vaccines. which the study does not seem to indicate, he said.
“It certainly escapes the immune response. It certainly is bad. But it seems to me that there are ways to deal with it.”
Sigal’s team used human lung cells for the tests. Blood from the six volunteers who were infected and later vaccinated was better able to neutralize the virus, they reported in a study not yet peer-reviewed.
“Previous infection, followed by vaccination or booster, will likely increase the level of neutralization and will likely provide protection against severe disease in Ômicron infection,” the team concluded.
The study does not reflect actual infection with the virus.
The researchers noted that the Beta variant, which spread across South Africa at an earlier time, also manages to evade immune protection. “The results we’ve presented here with the Ômicron show a much more extensive exhaust,” they wrote.
Other studies looking at immune protection against variants have shown that many of the Covid-19 vaccines create very strong immune protection that provides extra immunity – so that even if a variant escapes part of the immunity, there is still plenty to protect people from serious infections.
Importantly, the virus still attacks human cells via the same route as usual – a “molecular gate” called the ACE2 receptor.
“Imagine if this virus had found a different receptor to bind to?” Sigal asked. “So all our vaccines would not do,” he added.
Sigal is quick to say that this is a very initial study involving just 12 people and hastily cultured live virus samples. “We went from collecting samples to carrying out experiments and launching something in just a few weeks. It’s crazy,” he said.
The team plans to test more samples and test them against different vaccines, including Janssen’s, which has also been widely deployed in South Africa.
Reference: CNN Brasil
