JERUSALEM — Israel’s Health Ministry was weighing on Thursday whether to approve a fourth Covid-19 vaccine dose for some people to contain the fast-spreading Omicron variant, after experts recommended taking that step even before much scientific data was available to support another booster.
Despite the uncertainty, the pandemic response panel advising the government concluded that the potential benefits outweighed the risks, pointing to signs of waning immunity a few months after the third shot. It said that any delay in additional doses might prove too late to protect those most at risk.
If the Health Ministry approves the panel’s recommendation — which could happen imminently — Israel would be well ahead of other nations in administering a fourth dose. The prime minister, Naftali Bennett, has made clear he supports a fourth shot and Health Minister Nitzan Horowitz has suggested that a new round of boosters could get underway by Sunday.
“The price will be higher if we don’t vaccinate,” Dr. Boaz Lev, the head of the advisory panel, said at a news conference late Wednesday. Describing the spread of Omicron as “a kind of tsunami or tornado,” he added, “We don’t have a lot of time to make decisions.”
With Omicron sweeping the world at alarming speed, governments are scrambling to figure out how to contain it in the face of significant public pressure against reimposing harsh restrictions on daily life, curbing holiday celebrations and deepening the economic pain wrought by two years of pandemic.
Israel, a small country with an efficient public health system, moved very fast on vaccinating most of its nine million people and was among the first countries to approve a third dose of vaccines last summer. That has put Israel in position to detect early whether the boosters lose strength over time.
The proposal to give a fourth dose to those most at risk drew criticism from other scientists and medical professionals, who said it was premature and perhaps even counterproductive. Some experts have warned that too many shots eventually may lead to a sort of immune system fatigue, compromising the body’s ability to fight the virus.
A few members of the advisory panel raised that concern with respect to the elderly, according to a written summary of the discussion obtained by The New York Times.
Other Israeli experts said the government had still not made the most of other options, such as vaccinating more of the unvaccinated or giving a third shot to about a million eligible citizens who have so far not received one.
Along with the generally sparse knowledge about Omicron, the effect of a fourth dose against the new variant is also unknown. But the country’s medical experts point to waning immunity in those 60 or older, who were the first to receive the third shot starting in August.
Israeli researchers from the Health Ministry and several academic institutions presented data to the advisory team that made the recommendation for the fourth shot on Tuesday. The presentation, obtained by The Times, showed a doubling of the rate of infection from Delta among the 60-plus age group within four or five months of the third shot.
There was no clear indication of reduced efficacy against severe illness.
Israel has confirmed a few hundred cases of Omicron, but officials say the new variant is much more widespread, and could overtake Delta as the dominant variant in the country within two or three weeks.
Given the fear of a major Omicron outbreak during the winter, when the hospitals are already overflowing with patients with complications of flu and other respiratory ailments, the advisory panel voted overwhelmingly to recommend a fourth dose for people over 60, those with compromised immune systems and health workers, to be administered at least four months after their third shots.
The panel did not recommend a fourth shot for the wider population at this stage. But it did advise giving the third dose three months after the second, rather than the current wait of five months.
While there is evidence that Omicron, discovered just last month, usually causes milder illness than earlier variants, Israeli officials said that by the time they have clearer information, it might be too late to protect the people most at risk.
“We can sit in our academic armchairs and wait for research from abroad,” said Dr. Tal Brosh, another member of the advisory panel, “but that’s a kind of privilege we don’t feel we have.”
Last year, Israel led the world in vaccinating its population with two shots of the Pfizer-BioNTech vaccine. Mr. Bennett, the prime minister, prided himself on an early decision in late July to administer the third shot, crediting it with successfully containing the Delta wave while keeping schools and the economy open.
The emergence of Omicron threatens to reverse those gains and send the country back into a kind of lockdown. But Israel was quick to tighten border controls and bar most foreign nationals from visiting, and it is compiling an ever-growing red list of countries with high infection rates to which Israelis may not travel without special permission, including the United States and Canada.
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The Omicron variant. The highly transmissible Covid version appears to be less severe than previous variants, according to new studies. Research also suggests many non-mRNA vaccines offer almost no defense against infection, though the Pfizer and Moderna boosters, which are mRNA-based, most likely provide strong protection.
New treatments. The Food and Drug Administration authorized in short succession the first two pill treatments for Covid-19 from Pfizer and Merck. The new drugs, which can be taken at home with a doctor’s prescription, will be available to some Covid patients who are at higher risk of becoming severely ill.
Biden’s new plan. President Biden announced new steps to confront the surge in Covid cases, including setting up new testing sites and buying 500 million rapid tests to distribute free to the public. But experts warned the measures would not stop an Omicron surge, and it could be weeks until enough tests are available.
Around the world. After infections skyrocketed to record levels in South Africa, new cases have started falling, suggesting its Omicron wave may have peaked. In Europe, the Netherlands, Britain and Denmark adopted tough restrictions, while France, Spain and Italy are taking a more measured approach.
Mr. Bennett enthusiastically welcomed the panel’s recommendation of a fourth shot this week, saying, “The citizens of Israel were the first in the world to receive a third dose, and we are continuing to lead with the fourth.”
Germany’s health minister, Karl Lauterbach, said Thursday that he expected Germans would be getting another booster in the next year, depending on how long the protection of the third shot lasts.
But some medical professionals have suggested putting on the brakes.
Prof. Hagai Levine, an epidemiologist and chairman of the Israel Association of Public Health Physicians, said that Israel was not seeing a sharp rise in infections yet — daily infections are at around 1,200 a day, down from 11,000 at the peak of the Delta wave in August — and there was no evidence that a fourth shot was needed to prevent severe illness from Omicron.
“I respect the opinion of those who say better safe than sorry,” Professor Levine said in an interview, “and there is no problem with being prepared. But before giving a fourth shot, it is preferable to wait for the science.”
Another vocal critic, Prof. Dror Mevorach, who heads the coronavirus ward at the Hadassah Medical Center in Jerusalem, also urged waiting for more data.
“Just because we led with the third dose does not mean that there should be a fourth dose with no scientific basis,” he said. Decreasing antibodies over time is natural, he said, and boosting antibodies may have limited benefit.
The government advisory panel said its recommendation for a fourth shot stemmed from the particular confluence of Omicron and the additional burden on the health system during the winter, and may not lead so quickly to a fifth.
At first, many Israelis considered their country’s lead in vaccinating the public to be a privilege and a ticket to a quick return to normal life. But the prospect of a fourth vaccination within a year was giving some pause.
“Like many people, I’m very ambivalent,” said Chely Edery, 59, the owner of a gift store in Jerusalem. “The last thing I want is for my business to close, but I have the feeling that this time, they don’t know enough.”
Benny Muchawsky, 80, an architect, said it seemed like hysteria.
“Israel is the laboratory for the coronavirus vaccine,” he said.
Christopher F. Schuetze in Hanover, Germany contributed reporting.
