Israeli researchers have said they found a three-shot course of the Pfizer/BioNTech Covid-19 vaccine provided significant protection against the new Omicron variant.
The findings were similar to those presented by BioNTech and Pfizer earlier in the week, which were an early signal that booster shots could be key to protect against infection from the newly identified variant.
The study, carried out by Sheba Medical Centre and the country's health ministry's central virology laboratory, compared the blood of 20 people who had received two vaccine doses five to six months earlier to the same number of individuals who had received a booster a month before.
"People who received the second dose five or six months ago do not have any neutralisation ability against the Omicron. While they do have some against the Delta (strain)," Gili Regev-Yochay, director of the infectious diseases unit at Sheba, told reporters.
"The good news is that with the booster dose it increases about a hundred-fold. There is a significant protection of the booster dose. It is lower than the neutralisation ability against the Delta, about four times lower," she said.
The Israeli team said they worked with the actual virus while the companies used what is known as a pseudovirus, which was bio-engineered to have the hallmark mutations of Omicron.
The Israeli research follows a study from South Africa which found the Omicron variant can partially evade protection from two doses of the Covid vaccine.