Israeli report suggests fourth vaccine dose may provide only limited protection against Omicron

On Jan. 17, The Times of Israel reported on preliminary results from Sheeba Medical Center regarding Omicron infections after receipt of a fourth dose of the Pfizer mRNA vaccine. In an article titled “Israeli trial, world’s first, finds 4th dose ‘not good enough’ against Omicron,” the newspaper reported:

Nearly a month after Sheba Medical Center launched a landmark study to test the efficacy of a fourth COVID shot, the hospital said Monday that this fourth booster was only partially effective in protecting against the Omicron strain.

“The vaccine, which was very effective against the previous strains, is less effective against the Omicron strain,” Prof. Gili Regev-Yochay, a lead researcher in the experiment said.

“We see an increase in antibodies, higher than after the third dose,” Regev-Yochay said. “However, we see many infected with Omicron who received the fourth dose. Granted, a bit less than in the control group, but still a lot of infections,” she added.

“The bottom line is that the vaccine is excellent against the Alpha and Delta [variants], for Omicron it’s not good enough,” she said.

Meanwhile, in other reporting, discussion on Omicron-specific vaccines is ongoing. Initial data from studies by Pfizer and Moderna can be anticipated before the end of this March.

A Jan. 14 article in Scientific American titled “What’s holding up new Omicron Vaccines?” provides a discussion of issues and concerns, e.g., that a new variant might replace Omicron before Omicron-specific vaccines are available worldwide.

In my opinion, international coordination and analyses of such data, and its implications on total vaccine dose availability and vaccine inequity around the world, are essential. The initial results reported from Israel on the fourth dose of the Pfizer mRNA vaccine and protection against Omicron infection will give more urgency to Omicron-specific vaccine development, regulatory review, financial and geopolitical issues. WHO and partners in the COVAX initiative must be strongly involved.