Some 56 percent of Israelis have received both doses of the coronavirus vaccine, but a new percentage has raised its head: The highly contagious delta variant is now responsible for more than 90 percent of Israel’s cases, according to tests of the virus’ genome among confirmed cases.
The 90 percent was only 60 percent about two weeks ago; delta, which was first discovered in India, is clearly outpacing the alpha variant, which was first detected in the United Kingdom.
Still, Prof. Eran Segal, a computational biologist at the Weizmann Institute and a member of the Health Ministry’s advisory panel, says that despite the rise in confirmed cases, the case numbers are still “very, very low and we understand that the vaccine is effective.” Thus, he says, Israel “can avoid a return to severe restrictions.”
Israel’s first seven cases of delta were reported on April 16, when there were 77 cases in Britain, where the health officials upgraded delta’s severity to a “variant of concern” from a “variant under investigation.”
On April 16, Israel appeared to be almost completely past the crisis. Nearly 5 million of the country’s 9 million citizens had received both doses of the vaccine, and 11,000 tests produced 95 cases, with only 209 critically ill COVID-19 patients in the country’s hospitals.
In May and June, new-case numbers continued to decline; on some days only four newly infected people were identified. On June 1, Israel’s coronavirus restrictions were canceled, except for the requirement to wear a mask indoors in public places, and requirements remained for the isolation of unvaccinated people.
On June 15, the indoor mask requirement was lifted. Five days later there were delta outbreaks in the city of Modi’in halfway between Tel Aviv and Jerusalem, and in Binyamina north of Tel Aviv. On June 25, the indoor mask rule was reinstated.
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Thus in Israel it took two months from the first detection of the delta variant until the first outbreak. One reason is that delta was still less common around the world, so fewer Israelis were being exposed to it abroad. Plus the Israeli authorities were able to locate and isolate the first few delta patients. The high vaccination rate and the indoor mask requirement also helped delay the outbreak.
But Israel had one big shortcoming: As the delta variant spread abroad, the authorities were lax in ensuring the isolation of people entering the country. Also, vaccinated people returning from abroad were not required to isolate; vaccinated people do better against the alpha variant.
On Friday June 18, thousands of Israelis landed at Ben-Gurion Airport from abroad and were allowed to head home without being tested because the number of arrivals was great, on top of the pressure because the Sabbath was approaching. The following days saw outbreaks at schools, at least some of them traced to people returning from abroad who broke isolation.
A few days later the outbreak spread and within a week and a half people arriving from abroad were responsible for nearly 10 percent of infections.
The delta variant is more than twice as contagious as the original variant from China and more than one and a half times as contagious as the British variant. Still, experts are optimistic.
“I believe we still don’t know with certainty where we’re heading. We might stop at the current numbers and even see a decline, but there’s also the possibility of a rise in the numbers,” Segal of the Weizmann Institute says.
“What we do know is that if we vaccinate more people, the chance of stopping the current outbreak will be greater. Israel’s vaccination effort was sufficient when it came to the previous British variant .... The moment a more contagious variant came in, more people must be vaccinated.”
Last week about 100,000 people were inoculated, and they’ll need a month to be considered fully immunized. A big question will be Israel’s performance in the coming weeks; 12- to 15-year-olds are now being vaccinated in large numbers as well.
The experts are pinning their hopes on one important figure: the number of seriously ill patients. “We certainly see that the number of people developing severe symptoms among confirmed cases is significantly lower than before the era of the vaccine,” Segal says.
“This means that even if the number of confirmed cases goes up, we don’t expect to go back to hundreds of serious cases. For the number of serious cases to rise to where they were before the vaccine, Israel would have to see 15,000 to 20,000 new cases a day.”