Noam Kleinmann, 10, receives his first coronavirus disease (COVID-19) vaccination after country approves vaccinations for children aged 5-11, in Tel Aviv, Israel November 22, 2021. REUTERS/Corinna Kern

Israeli researchers have seen the third booster vaccine shot provide “significant” protection against infection and severe illness from the Omicron coronavirus variant, in a new study.

According to findings of the study, carried out by Sheba Medical Center and the Israel Health Ministry’s Central Virology Laboratory, a three-shot inoculation of the Pfizer-BioNTech COVID-19 vaccine is expected to protect from the breakout of severe disease. Conversely, vaccination with two full Pfizer-BioNTech doses was ineffective at preventing COVID-19 caused by the Omicron variant.

“The bad news is that people who received the second dose five or six months ago do not have any neutralization ability against the Omicron variant. While they do have some against the Delta [strain],” said Gili Regev-Yochay, director of the Infectious Diseases Unit at Sheba, during a briefing.

“The good news is that with the booster dose there is significant protection. The booster dose increases protection against Omicron about a hundred fold,” Regev-Yochay added.

Regev-Yochay conceded that although “it is lower than the neutralization ability against the Delta, about four times lower,” she is “optimistic” that the booster dose will protect many people from getting infected by the Omicron variant in the first place and those who do get infected from getting seriously ill.

The study was based on the examination of blood samples from 20 Sheba health workers who received a third Pfizer booster shot a month ago compared with the bloodwork of another 20 staff member who were vaccinated with two doses five or six months ago.

“The findings underscore the importance of raising vaccination rates as the most effective and necessary step toward cutting infection rates and slowing the spread of the virus,” remarked Regev-Yochay.

The overall results of the initial study will later be peer reviewed and are expected to be published in the New England Journal of Medicine.

At the end of November, Sheba Medical Center reported that two Israeli doctors had been infected with the Omicron variant — one having returned from a conference in London in the week before detection. The two doctors had received three doses of the Pfizer/BioNTech vaccine, and had shown mild COVID-19 symptoms, the hospital said.