Israeli study: 4th shots were key to saving lives among over-60s in Omicron wave

Research by Clalit, not yet peer-reviewed, shows just one fully-boosted elderly Israeli died for every five un-boosted – raising question of how many could have been saved globally

Nathan Jeffay is The Times of Israel's health and science correspondent

An Israeli man receives a second booster of the COVID-19 vaccine in Modi'in, on January 6, 2022. (Yossi Aloni/Flash90)
An Israeli man receives a second booster of the COVID-19 vaccine in Modi'in, on January 6, 2022. (Yossi Aloni/Flash90)

New Israeli research indicates fourth shots of the Pfizer–BioNTech coronavirus vaccine significantly curtailed deaths in Israel’s older population during the Omicron wave.

It also raises the question of how many lives may have been lost due to the world’s slow adoption of fourth shots.

Israelis who topped up their triple-vaccine protection with a fourth shot of the vaccine reduced their chances of death by 78 percent, according to Clalit Health Services and Sapir College.

This was calculated by studying death rates among Israelis aged 60-plus who were four months after their third vaccine, over a 40-day period during the Omicron wave. For every five deaths among those who didn’t get a fourth shot, there was just one death among those who did.

The study, which has been published online but not yet peer-reviewed, comes three months after Israel went out on a limb internationally by introducing second boosters for the elderly, at-risk individuals and medical staff.

Other countries have either not yet started re-boosting — such as the US, which is expected to start soon — or only done so more recently, as in the case of the UK. The World Health Organization strongly opposed both third and fourth shots until three weeks ago, when it reversed its position and said they are needed.

The new study gives a far more optimistic view of the impact of second boosters than recent research by Israel’s largest hospital. That study focused on younger people, and looked mainly at infection and illness rather than death. Experts had been waiting for research based on the elderly and looking at death rates.

The Clalit research does this, and includes anonymized data from 563,465 Israelis aged 60-plus, 58% of whom received a second booster. After crunching mortality data and adjusting it for demographic factors and preexisting illnesses, scientists found a dramatic mortality reduction among the re-boosted.

“This study demonstrates a substantial reduction in COVID-19 mortality by the second-booster in eligible subjects,” they wrote.

A health worker prepares to give a dose of the COVID-19 vaccine at a Clalit Health Services center in Katzrin, Golan Heights, January 9, 2022. (Michael Giladi/Flash90)

On the topic of second booster policy around the world, lead author Dr. Ronen Arbel, a Sapir College academic who is Health Outcomes Researcher at Clalit, and his colleagues wrote that “providing the second booster dose is still highly controversial, mainly because of the lack of evidence of effectiveness and major concerns regarding global vaccine inequity.”

But the study “may provide primary evidence regarding the life-saving potential of an additional booster dose,” they added.

Speaking to The Times of Israel, Arbel would not speculate on how many Omicron deaths internationally may have been prevented by quicker second booster adoption.

However, he said that “hundreds of lives” could have been saved in Israel alone had elderly people who failed to re-boost done so.

Illustrative image: A burial services employee with the remains of a coronavirus victim on January 28, 2021. (Gili Yaari / Flash90)

Arbel said the study has an immediate message for elderly Israelis. “If you’re over 60 and had a first booster four or more months ago in Israel, you should get a fourth shot,” he said.

In every age group over 60, the impact of second boosters was starkly apparent.

Among participants aged 60-69, there were five deaths among the 111,776 people who had second boosters, while among the 123,786 who didn’t, there were 32 deaths.

There were 22 deaths among the 134,656 people aged 70-79 who took second boosters, while there were 51 deaths among a much smaller 74,717-person cohort of those who didn’t get the additional shot.

In ages 80-100, there were 65 deaths among the 82,165 people who did get second boosters, and 149 deaths among the 36,365 who didn’t.

Arbel commented: “Research from Sheba has suggested that the fourth shot isn’t so effective at preventing infection, but that’s actually not the game — the real game is reducing deaths, and in that, it’s really effective.”

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