Israeli vaccine study finds people still catching Omicron after 4 doses

• Four vaccine shots didn't stop people from catching Omicron, an official from an Israeli trial said.
• The trial compared people with a fourth dose to those with three, and found little difference.

A landmark Israeli trial is expected to show that four shots of vaccine didn't stop infection by the Omicron variant, according to a study official.

While the extra dose — of either Pfizer of Moderna vaccine — seemed to have some effect, rates of infection in the study were not substantially different to those who had three doses of Pfizer, the study official said.

Gili Regev-Yochay, a lead investigator on the study, told reporters that "the vaccine is excellent against the Alpha and Delta," but the study found that "for Omicron, it's not good enough," The Times of Israel reported Monday evening.

The investigator did not release data from the trial, noting that the results are preliminary. But she said she shared the early findings as there was a large public interest, per The Times of Israel.

The findings, if confirmed and vetted by other scientists after publication, could bolster calls for the development of a new version of the COVID-19 vaccines. Some new types of vaccines are already in the early stages of development.

The Israeli trial, launched by the Sheba Medical Center a month ago, is investigating the effect of the Pfizer booster in 154 people and the Moderna booster in 120 people, per Reuters.

It found that there was an "increase in antibodies" among those who got the fourth shot.

But Regev-Yochay said: "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," per the Times of Israel.

The control group were people who had three doses of the Pfizer vaccine.

About 500,000 fourth shots of vaccine had been administered in Israel as of Sunday, per the Times of Israel.

Vaccines are still protective against severe disease and hospitalization.

Figures from the UK health security agency published December 31 found that two doses of vaccine reduced the risk of hospitalization by 72% within 24 weeks of the second shot.

That protection waned over time, but a third shot boosted it back up, reducing the risk of hospitalization by 88% for at least two weeks.

Scientists hoped that heightened levels of antibodies after a booster shot, which were also seen after the third shot, could mean that the body would be able to ward off infection and transmission from Omicron.

But lab studies have found that the Omicron variant is very adept at dodging antibodies, which had been able to block previous variants of the coronavirus.

"We know by now that the level of antibodies needed to protect and not to get infected from Omicron is probably too high for the vaccine, even if it's a good vaccine," said Regev-Yochay, per Reuters

Israel, which has already given a third shot of vaccine to more than 45% of its people as of late December, has seen a surge in cases driven by Omicron, although deaths have remained low.

"This graph of their Omicron wave isn't encouraging vs infections with 3rd booster," Eric Topol, director of the Scripps Research Translational Institute, tweeted Monday.