Washington, Dec 8 : Pfizer on Wednesday announced that a third dose of its mRNA vaccine can protect against the Omicron variant of Covid-19.
Results from an initial laboratory study demonstrated that serum antibodies induced by the Pfizer-BioNTech Covid-19 vaccine (BNT162b2) neutralises the SARS-CoV-2 Omicron variant after three doses, the company said in a statement.
These antibody levels are associated with high efficacy against both the wild-type virus and these variants. A third dose also strongly increases CD8+ T cell levels against multiple spike proteins which are considered to correlate with the protection against severe disease.
Compared to the wild-type virus, the vast majority of these remain unchanged in the Omicron spike variant, the company said.
"Sera obtained from vaccines one month after receiving the booster vaccination (third dose of BNT162b2 vaccine) neutralised the Omicron variant to levels that are comparable to those observed for the wild-type SARS-CoV-2 spike protein after two doses," it said.
Sera from individuals who received two doses of the current Covid-19 vaccine did exhibit, on average, more than a 25-fold reduction in neutralisation titers against the Omicron variant compared to wild-type, indicating that two doses of BNT162b2 may not be sufficient to protect against infection with the Omicron variant.
However, the company believes that vaccinated individuals may still be protected against severe forms of the disease and are closely monitoring real world effectiveness against Omicron, globally.
Data from additional studies indicate that a booster with the current Covid-19 vaccine from Pfizer and BioNTech increases the antibody titers by 25-fold.
"Although two doses of the vaccine may still offer protection against severe disease caused by the Omicron strain, it's clear from these preliminary data that protection is improved with a third dose of our vaccine," said Albert Bourla, Chairman and Chief Executive Officer, Pfizer, in the statement.
"Broad vaccination and booster campaigns around the world could help us to better protect people everywhere and to get through the winter season," added Ugur Sahin, CEO and Co-Founder of BioNTech.
He also said that the company will "continue to work on an adapted vaccine which will help to induce a high level of protection against Omicron-induced Covid-19 disease as well as a prolonged protection compared to the current vaccine".
Meanwhile, a small study led by South African researchers showed that Pfizer's Covid vaccine may be up to 40 times less effective against the new super mutant Omicron variant compared with the original virus.
But, Omicron's ability to escape vaccine antibodies is "incomplete", said Prof Alex Sigal, a virologist at the Africa Health Research Institute, who led the research.
"Previous infection, followed by vaccination or booster is likely to increase the neutralisation level and likely confer protection from severe disease in Omicron infection," he added.
Moderna and Johnson & Johnson are also expected to release lab results from the Omicron variant in the coming days.
In an interview with The Wall Street Journal, Bourla said that company should have been more mindful of lack of facilities, the infrastructure as well as vaccine hesitancy hurdles faced by poor countries, even as the drugmaker sent more doses to low-income countries after ramping up manufacturing.
"We should have done it better," he said on Tuesday at The Wall Street Journal's CEO Council.
The company could have partnered earlier with NGOs to help address vaccine hesitancy. He praised a recent effort to do so by the World Health Organisation, but noted "that's something that we could have done ourselves".
Further, he stated that the Omicron variant which causes Covid-19 appears to be milder than previous strains, but also seems to spread faster and could lead to more mutations in the future.
"I don't think it's good news to have something that spreads fast," he said. "Spreads fast means that it will be in billions of people and another mutation may come. You don't want that." Bourla also said that is hopeful that the US Food and Drug Administration will this month authorise the company's Covid-19 drug Paxlovid. The pill was found in a preliminary look of late-stage study results to be 89 per cent effective at reducing the risk of hospitalisation and death.
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