Israel’s Health Ministry was weighing on Thursday whether to approve giving people a fourth Covid-19 vaccine dose to try to contain the fast-spreading Omicron variant, after the experts who recommended it said they believed they had to act even before much scientific data was available to support another booster.
Despite the uncertainty, the pandemic response panel advising Israel’s government concluded that the potential benefits outweighed the risks, pointing to signs of waning immunity a few months after the third shot. They said that any delay in additional vaccines might prove too late to protect those most at risk.
If the Health Ministry approves the panel’s recommendation — which could happen as early as Thursday — Israel would be well ahead of other nations in administering a fourth dose. 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.”
Still, the experts’ recommendation for a fourth dose to those most at risk drew criticism from other scientists and medical professionals within Israel as premature and perhaps even counterproductive. Some scientists have warned that getting too many shots may eventually lead to a sort of immune system fatigue, compromising the body’s ability to respond to the virus.
A few members of the advisory panel raised a concern about a fading or exhausting of the immunological response in the elderly following multiple vaccinations within a short period of time, according to a written summary of the discussion obtained by The New York Times.
Along with the generally sparse knowledge about Omicron, the effect of a fourth dose against the new variant is also untested and unknown.
Israel was among the first countries to offer its residents a third shot, starting last summer. Now, the country’s medical experts are pointing to waning of immunity in those 60 or older, who were the first to receive the third shot starting in August.
Israel has confirmed only a few hundred cases of Omicron, but officials say they believe that the new variant is much more widespread, and that it could overtake Delta as the dominant strain in the country within two or three weeks.
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 New York 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 is no clear indication of reduced efficacy against severe illness. But given the fear of a major Omicron outbreak during the winter months, when the hospitals are already overflowing with patients with complications of flu and other respiratory ailments, the advisory panel members voted overwhelmingly to recommend a fourth dose for people aged 60 and over and the immuno-compromised, as well as health workers, to be administered at least four months after their third shot.
The panel did not recommend a fourth shot for the wider population at this stage. It did favor bringing forward the third shot to three months after the second dose, as opposed to the previous recommendation of five months.
While there are some initial indications from South Africa and other countries that Omicron infections more often result in mild illness than earlier variants, the Israeli officials said that by the time they had 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.”