Study finds fourth jab not effective enough against Omicron

Prof. Gili Regev-Yochay Photo: Ilya Melnikov

Data from research headed by Prof. Gili Regev-Yochay indicate that it is not worthwhile expanding administering the fourth dose to the population at large in Israel.

New data from serological research at Sheba Medical Center in Israel have found that although a fourth Pfizer or Moderna Covid vaccination significantly increases the level of antibodies against Covid, it is not strong enough to cope with the Omicron variant. The research headed by Prof. Gili Regev-Yochay examined morbidity among Sheba employees and found that although the fourth vaccination raised the number of antibodies, high numbers still tested positive for Omicron.

Regev-Yochay stressed that these were still preliminary results. She added that the numbers examined would not be published, because there was importance to the period of time after receiving the vaccination, and the current numbers would only be confusing. She said that the Omicron infection of 270 participants in the research was significant.

The fourth vaccination was not completely ineffective against Omicron but the variant was successful in partially evading it. It was not clear whether the fourth vaccination adds protection against severe illness, beyond that provided by the third booster dose. At the moment no severe illness with Omicron has been seen among the trial's participants in the fourth vaccination, but then neither has it been seen among those with three doses.

Israel approved a fourth Covid vaccination immediately after the outbreak of the Omicron variant, without any special research, based on the success of the third vaccination against the Delta variant last summer, even though the vaccine was not designed for it. However, it seems that Omicron has moved even further away from the original Covid, for which the vaccine was designed.

It still does not neccessarily mean that the fourth jab has been entirely superfluous for all the 537,500 Israelis who have received it. The Delta variant is still infecting many Israelis and is probably responsible for many of those who are seriously ill with Covid. The fourth vaccination adds protection for those whose antibodies have started fading from the third jab. The fourth vaccination might also add protection against serious infection.

However, the data indicate that it is not worthwhile expanding administering the fourth dose to the population at large. Until now only over 60s and high-risk groups have been eligible for a fourth vaccination in Israel.

The data also show that it is worthwhile developing a vaccine specifically targeting Omicron for high-risk groups and readying to more swiftly develop vaccination for the next variants, which could be more infectious and more aggressive than Omicron. The existing vaccine won't necessarily work well against them.

Published by Globes, Israel business news - - on January 17, 2022.

© Copyright of Globes Publisher Itonut (1983) Ltd., 2022.

Prof. Gili Regev-Yochay Photo: Ilya Melnikov
Prof. Gili Regev-Yochay Photo: Ilya Melnikov
Shirit Avitan Cohen, Michal Raz Chaimovitz, and Gali Weinreb
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