Two doses of the Pfizer/BioNTech jab might not be enough to protect people against the Covid-19 Omicron strain, the US pharma giant said, citing its own study and adding that one more booster shot could still do the trick.
The vaccine developed together by the American and German manufacturers appears to be 25 times less effective against the Omicron variant than it is against the original Covid-19 strain, the US company said on Wednesday in a press release, citing the results of its own "initial" study.
Sera from individuals who received two doses of the vaccine demonstrate "more than a 25-fold reduction in neutralization titers against the Omicron variant" compared to the original strain, the press release said. The company still believes that its jab is capable of providing some level of protection against "severe form of the disease" since most of the virus parts targeted by the vaccine-induced T-cells have not mutated in the Omicron strain.
People can still raise their protection level with a booster shot that would bring it back to normal, the company added. A booster shot "increases the antibody titers by 25-fold" and thus "provides a similar level of neutralizing antibodies to Omicron" as the two doses do against all previous Covid-19 strains, Pfizer said, citing some "additional studies" and "preliminary data."
"Our preliminary, first dataset indicate that a third dose could still offer a sufficient level of protection from disease of any severity caused by the Omicron variant," said Ugur Sahin, the BioNTech CEO. "Broad vaccination and booster campaigns around the world could help us to better protect people everywhere and to get through the winter season," he added while saying that the two companies are currently working on an "adapted vaccine."
Earlier on Wednesday, a group of South African scientists also said that Omicron appears to be partially escaping immune response induced by the Pfizer jab, adding that people who got two shots of the vaccine and were previously infected with Covid-19 appear to have the highest level of protection against the new strain. Their data was based on the analysis of samples from just 12 people, though.
The Omicron strain that was recently discovered in South Africa and has since spread to the other parts of the world, including Europe, is widely believed to be highly contagious. Some scientists fear it can escape vaccine-induced immune responses at least partially due to a high number of mutations, including in its spike protein. The World Health Organization's scientists believe, though, it is no more severe than any other Covid-19 strain.