An elderly Israeli woman is injected with the fourth COVID-19 Pfizer/BioNTech vaccine by a Magen David Adam National Emergency Services worker in the Migdal Nofim Assisted Living Facility in Jerusalem, on January 6. A new study from Israel suggested a fourth shot may not be enough against the Omicron variant. Photo by Debbie Hill/UPI | License Photo
Jan. 18 (UPI) -- A fourth dose of the Pfizer/BioNTech coronavirus vaccine may not be enough to protect people from getting infected with the Omicron variant of COVID-19, a new Israeli study released Tuesday suggests.
The study, conducted on 150 healthcare workers at the Sheba Medical Center, showed that the vaccine increased antibody levels in blood, but it was simply not enough the handle the constantly changing Omicron variant.
"Two weeks after administering the fourth vaccine, we see a good increase in the antibodies, higher than after the third dose, but not high enough against Omicron," lead researcher Gili Regev-Yochay said.
"People are getting infected, maybe in slightly lower numbers compared to individuals in the control group, but not lower in any significant way."
The center started the clinical trial to examine the safety and efficacy of a fourth Pfizer shot on Dec. 27, administering the inoculation to 150 healthy staff members who had been boosted at least four months earlier.
Regev-Yochay said the antibody level in early January increased five-fold a week after the fourth shot, which she described as a nice result similar to the one after the third shot.
While the hospital did not release more specific data, Regev-Yochay said the results of the research are only preliminary -- but released it because of its high public interest.
More than 500,000 Israelis have been inoculated with a fourth dose as of Sunday after the Israeli health ministry started offering the shots to Israelis 60 and older.