JERUSALEM, Jan 17 (Reuters) - A fourth shot of COVID-19
vaccine boosts antibodies to even higher levels than the third
jab but it is not enough to prevent Omicron infections,
according to a preliminary study in Israel.
Israel's Sheba Medical Center has given second booster shots
in a trial among its staff and is studying the effect of the
Pfizer booster in 154 people after two weeks and the Moderna
booster in 120 people after one week, said Gili Regev-Yochay,
director of the Infectious Diseases Unit.
These were compared to a control group that did not receive
the fourth shot. Those in the Moderna group had previously
received three shots of Pfizer's vaccine, the hospital said.
The vaccines led to a increase in the number of antibodies
"even a little bit higher than what we had after the third
dose," said Regev-Yochay.
"Yet, this is probably not enough for the Omicron," she told
reporters. "We know by now that the level of antibodies needed
to protect and not to got infected from Omicron is probably too
high for the vaccine, even if it's a good vaccine."
The findings, which the hospital said were the first of its
kind in the world, were preliminary and not yet published.
Israel was the fastest country to roll out initial
vaccinations against COVID-19 a year ago and last month started
offering a fourth shot, or a second booster, to the most
vulnerable and high-risk groups.
(Reporting by Ari Rabinovitch
Editing by Mark Heinrich)