Pfizer booster shots are effective against Omicron variants, says Israeli study

Findings, similar to those announced last week by Pfizer, suggest that countries concerned about the rapid spread of omicrons will be better able to protect their populations with continued vaccination.

Researchers from Sheba Medical Center and the Israeli Ministry of Health examined blood samples from 20 Sheba employees who had received boosters within the past five to six months, and 20 workers who were five or six months before their second shot and did not receive There is a third shot.

The crews who received the booster showed a neutrality level of about 100 times higher than the two-shot group against the Omicron version. However, among those who had booster shots, the level of neutralization was four times lower for Omicron than in Delta, still the most prevalent strain of the virus circulating globally.

Study concludes: People who received boosters may be more likely to be infected with Omicron than other variants, but they would not be more likely to develop serious illness or be hospitalized, Infectious-Disease Epidemiology in Shiba The director of the unit, Gili Regev-Yochay, said. Medical Center, at a news conference Saturday night.

The bad news of the study, said Dr. Regev-Yoke, is that those who “received a second dose of vaccine five to six months earlier had no neutralization potential.”

“If you’ve been there for the past five months and haven’t got a booster, get it,” Dr. Regev-Yochay said.

Those in the two-shot group still showed some protection against the Delta version. The findings will be published soon in the New England Journal of Medicine. The study was based on a few dozen blood samples, Dr. Regev-Yochay said, calling it “relatively good size” for such a study.

Last week Pfizer said the third dose of its vaccine increased antibodies against Omicron by 25 times compared to two doses.

Studies by Israeli researchers and Pfizer, and a study by scientists in South Africa, where the Omicron variant was first detected, suggest that three doses are needed to produce an effective immune response against Omicron. against earlier virus strains provided by just two doses. ,

The authors of the Israeli study said their effort was first to combine an actual sample of the Omicron version grown in a lab with blood samples from individuals who had received a booster shot. The Pfizer research was conducted on a pseudovirus that was intended to mimic the original.

Pfizer and BioNTech are working on an Omicron-specific vaccine, which is expected to be available by March 2022, if by then the variant becomes widespread. Shortly after Omicron was identified, researchers began work on the new vaccine on November 25.