An Israeli hospital has administered fourth COVID-19 vaccine doses to a test group of health workers, in what it called the first major study into whether a second round of boosters will help contend with the fast-spreading Omicron variant.
Results of the trial, likely to be closely watched internationally, will be submitted to Israel’s Health Ministry in about two weeks, said a spokesperson for Sheba Medical Centre near Tel Aviv.
Israel was the fastest country to roll out initial vaccinations a year ago, and became one of the first to launch a booster programme after observing that immunity waned over time.
With hospital admissions again climbing as Omicron spreads, a ministry expert panel last week recommended Israel become the first country to offer a second booster – initially to medical workers and those over 60 or with compromised immune systems.
The proposal was welcomed by the Israeli government, which has struggled against a plateauing of turn-out for vaccines. But the expert panel was divided over whether there is enough scientific data yet to justify fourth shots.
Final approval by Health Ministry director-general Nachman Ash is still pending, and Israeli media say he may limit fourth shots to over 70s.
“The biggest question is, how significant is Omicron? It’s clear to all that it is very contagious. But whether it causes very severe illness – that’s the most significant question,” said Gili Regev-Yochay, who is running the Sheba trial.