Is another COVID booster shot that we beat Omicron? Israel is putting the theory to the test

While Omicron is on fire around the world, defying health measures and border restrictions, governments have been forced to abandon vaccination efforts and hospitals have prepared for an increase in the number of new patients.

In Israel, where Omicron has not yet gained a significant foothold, public health experts warn that the country is less than a week away from an increase of tens of thousands of new infections a day.

With the next wave approaching, Israel has now approved something that no country has tried before: issuing a fourth dose of vaccine to its most vulnerable people.

A vaccine advisory panel of 80 public health experts voted last week to recommend that the fourth dose be given to the country’s over 60s and health workers.

Health Director General Nachman Ash announced the final approval at a press conference late Thursday (local time).

As time runs out quickly before infections are expected to swell next week, experts largely agreed on the benefits of recommending a fourth dose – even without any data to support it.

“There is no evidence that a fourth dose helps. And there is no evidence that it does not harm,” said Professor Ron Dagan, a pediatrician and expert in infectious diseases who is a member of the vaccine advisory panel and voted in favor of the recommendation. .

“But you still have to make a decision.”

The billion question: Will another booster work?

A country with more than 9 million, Israel bet early and heavily on vaccination as a ticket out of the pandemic.

An agreement cut between its former prime minister and Pfizer’s CEO last year ensured a supply of millions of doses for far-reaching inoculation of citizens in early 2021, much faster than the rest of the world.

Half a year later, it led the world with its booster campaign, which helped tame its deadly fourth wave of the Delta variant within weeks.

An initial trial of a fourth dose began on Monday among 150 employees at Sheba Medical Center on the outskirts of Tel Aviv and was to give health authorities an early insight into its effectiveness within just a few weeks.

“The billion-dollar question is about efficiency,” said Nadav Davidovitch, a public health professor at Ben-Gurion University who also sits on Israel’s advisory panel.

Studies have shown that those vaccinated with a third shot have a stronger immune response to Omicron than those vaccinated with only two doses.

However, Israeli researchers have noticed a significant weakening of immunity among the triple-vaccinated in the four months after the third shot.

Similarly, a briefing published by the UK Health Security Agency before Christmas suggested that booster shots lost up to 25 percent effectiveness against Omicron after just 10 weeks.

A man uses three masks to cover his entire face with holes cut out so he can see
Israel has used mask mandates and widespread testing in connection with a rigorous vaccination program to try to deal with COVID. (Reuters: Ronen Zvulun)

The declining immunity from boosters has not extinguished the hope that the fourth shot can provide the strongest immune response to date in both the number and quality of antibodies it generates.

But the opposite can also happen. One possible scenario is that the fourth dose does nothing to protect the vulnerable from Omicron in the same way that the third did against Delta, according to Daniel Cohen, professor of epidemiology and preventive medicine at Tel Aviv University.

Another possible disadvantage of a fourth shot is the chance that repeated vaccination may somehow erode the body’s immune response, which has sometimes been observed in other multidose vaccines.

“You can get these forms of tolerability or desensitization of cells in the immune system,” Professor Cohen said, explaining that this could make the vaccine impotent against disease.

These concerns, along with others, are seen by some Israeli experts as minor consequential risks weighted against the potential protection a fourth dose could offer in the way of an incoming tidal wave of Omicron – although this potential is not grounded in any data.

“The most reasonable thing that can be bad is that it does not work,” Professor Dagan said.

“If this is the worst case scenario, then fine, let’s go and do it.”

Israel could once again become the litmus test for the rest of the world

The approval for the fourth shot is just that.

In the meantime, other countries will look with interest, though vaccination efforts are lagging elsewhere and remain uneven globally.

The data provided by the fourth shot can inform other wealthy countries’ decisions on whether to roll out their own fourth-dose programs.

The coming weeks of Omicron’s spread in Israel may also prove important in trying to understand how vaccination may play a role in the future management of the pandemic, including the possibility of a fifth dose or more down the track.

“No one really knows,” Professor Davidovitch said of the potential for more regular boosters.

“But I think if I make a qualified guess, probably not.”

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