A new Israeli study strengthens evidence that getting fourth shots of the coronavirus vaccine curtailed deaths in Israel, showing that the Pfizer boosters halved the chances of death from COVID among severe hospitalized patients over age 60.
The study by Assuta Ashdod University Hospital, which has not yet been peer-reviewed, also found that fourth shots halve the odds that a patient will need ventilation.
“In short, they appear to significantly reduce the two worst outcomes — death and ventilation,” Dr. Tal Brosh, who led the comparison of outcomes among three-shot receipts and four-shot recipients, told The Times of Israel.
Brosh, infectious diseases director at Assuta Ashdod and coordinator of Israel’s Epidemic Management Team which advises government, said the stark result suggests that it may be wise to give new boosters to at-risk groups as each new coronavirus wave hits.
Acting before others, Israel offered fourth doses to the elderly and at-risk populations, as well as medical workers this winter, as Omicron hit the country hard.
Brosh said: “What we found was that those with four vaccines have half the chance of being ventilated or dying. In other words, your vaccines have failed you in preventing infection, and in preventing deterioration to the point of hospitalization — but still, once you’re in hospital, they make a difference.”
The 1,049 people whose severe cases were reviewed in the study were all aged 60-plus, and admitted to one of 14 Israeli hospitals that participated in the research, during the last two weeks of January.
Of the over-60s who were hospitalized in serious condition, some 50 percent with three doses died, while the rate for those with four vaccine doses was 30%. After applying statistical tools to accommodate for other differences between these two groups, the risk of dying or getting ventilated was two-fold lower for four-dose vaccinees.
Brosh commented: “I believe it’s not so much how many doses [you’ve had], but how freshly boosted you are, and this should influence thinking in future waves.”
Brosh added that, as the vast majority of those who ended up in the hospital were elderly and at-risk, he does not see a need for extra boosters for the general population at the moment.
“The basic immunization schedule should be three doses for most people, but the vulnerable people, elderly, immunosuppressed and people with significant co-morbidities should have boosters in future,” he said.
The first research on fourth shots in Israel, conducted among health workers not among the elderly, generated circumspect results, but more recent studies have been more optimistic. They included one released last week, which concluded that the fourth significantly boosts protection against severe illness in older adults, and another from late March which found that extra boosters significantly curtailed deaths in Israel’s older population during the Omicron wave.