4th Vax Shot ‘Not Good Enough’ To Protect Against Omicron: Israeli Researcher

A fourth Covid-19 vaccine dose may provide only limited protection against infection from the omicron variant, an Israeli researcher studying the shots said Monday based on preliminary findings, as a number of countries roll out the extra booster shots to at-risk groups.

While the fourth dose increased antibodies that protect against Covid-19 to a higher level than after three shots, it is “not good enough” to completely protect against an infection from the omicron variant, Prof. Gili Regev-Yochay, the director of Sheba Medical Center’s infectious disease unit and a lead researcher on the study, told reporters.

There were still “a lot of infections” of the omicron variant among those who received a fourth shot, though the number was slightly lower than among those who hadn’t gotten that extra dose, Regev-Yochay said, as reported by the Times of Israel.

Regev-Yochay said it’s still “likely” a good idea to roll out fourth doses to those who are at the highest risk, the Times of Israel reports, but suggested it may be better to only give older senior citizens the extra shot rather than everyone over age 60, as Israel is doing now.

Regev-Yochay did not release more specific data from the trial or comment on the fourth shot’s effectiveness against hospitalization or death against omicron, though the initial booster shots are highly protective against severe illness from the variant.

Sheba Medical Center’s study is based on 154 people who received four doses of the Pfizer/BioNTech vaccine and 120 people who received three Pfizer doses and one Moderna dose, Reuters reports, and the Times of Israel notes it’s so far the only known study that’s come out on the fourth dose’s effects.

The findings are still preliminary and have not yet been published or peer reviewed.

The increase in antibodies from the fourth shot “is probably not enough for the omicron [variant],” Regev-Yochay told reporters, as reported by Reuters. “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.”

More than 500,000. That’s how many Israelis have so far received a fourth vaccine dose, according to the Times of Israel. Only immunocompromised residents, senior citizens and healthcare workers are so far eligible for the extra shot.

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