“When we looked at the third wave, we left it behind although a third of our population – mostly children – were not vaccinated,” she recalled. “At the time we did not know it, but in retrospect, our numbers were down because there were enough vaccinated people to get to herd immunity. This protected the children.”

After the Delta variant became dominant, the situation changed.

“The infectiousness of Delta is higher and therefore the level needed for herd immunity is higher,” Alroy-Preis said. “We do not know what the exact number is but I believe that what we are seeing now is that Israel is again getting to a place where enough people are vaccinated or recovered to reach herd immunity.”

During the fourth wave which started around mid-June, more than half (55%) of the cases have been among children too young to be vaccinated and cases of serious post-COVID syndrome symptoms among the young have increased.