4th Vaccine Shot Likely ‘Not Good Enough’ To Protect Against Omicron, Israeli Researcher Says

Topline

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.

Moshe Geva Rosso receives a fourth dose of the Covid-19 vaccine on December 31, 2021 in Ramat Gan, … [+] Israel.

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Key Facts

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.

Crucial Quote

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.”

Big Number

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.

Key Background

Israel became the first country to roll out fourth vaccine shots starting in late December, and several other countries including Chile and Denmark have since followed with their own plans to administer the extra doses. The fourth shots come in response to evidence suggesting the initial booster shot’s effectiveness wanes over time, with the U.K. Health Security Agency finding they’re often far less effective at preventing infections within 10 weeks. The countries’ fourth shot rollouts have taken place despite a lack of evidence regarding whether the shots are effective, and Pfizer CEO Albert Bourla said last week he still “[doesn’t] know whether there’s a need for them” since their effectiveness hasn’t been fully studied yet. Some experts had cautioned against Israel and other countries administering the extra shots as a result, with Israel Association of Public Health Physicians chairman Professor Hagai Levine telling the New York Times in December, “Before giving a fourth shot, it is preferable to wait for the science.”

What To Watch For

Pfizer/BioNTech intends to have an updated version of their vaccine designed to protect against omicron ready in March. Bourla said during the J.P. Morgan Healthcare Conference last week it could be better to administer that than a fourth shot of the companies’ original vaccine, if the data bears that out.

Tangent

West Virginia Gov. Jim Justice (R) said in early January the state would ask the Centers for Disease Control and Prevention to let them start administering fourth shots, given West Virginia’s particularly high vulnerable population. The CDC has so far resisted supporting extra booster doses, however, and director Dr. Rochelle Walensky said during a recent press briefing the agency’s “strategy has to be to maximize the protection of the tens of millions of people who continue to be eligible for a third shot before we start thinking about what a fourth shot would look like.”