But concerns were mounting that measures intended to isolate religious scholars in groups had proved inadequate to contain the disease. At a yeshiva in Jerusalem run by the Ger Hasidic sect, about 340 out of 2,000 students tested positive, the newspaper Haaretz reported, but hundreds more returned to their homes for the holiday weekend without being tested, raising the specter that many were spreading the virus.
The Health Ministry said late Saturday that 13.7 percent of coronavirus tests had come back positive in the prior 24 hours, with more than 9,200 new cases reported, a record. About 750 people were in critical condition, nearing the 800-patient threshold at which officials have warned that the health care system could collapse.
There were also ominous-sounding reports that the virus was beginning to afflict younger people in greater numbers. Eran Segal, a scientist at the Weizmann Institute, noted a decline in the median age of the deceased.
“It is not clear why,” he wrote on Twitter. “Better care for adults? Or worse care for young people? Or worse care for all because of the load?”
And in Bnei Brak, Dr. Eliyahu Sorkin, director of intensive care at Mayanei Hayeshua Medical Center, said that 40 percent of its most serious patients, many of them needing respirators, were now age 19 to 50. “This is a completely new thing,” he said. “We do not know this disease.”
With Yom Kippur’s day of fasting and somber remembrance starting Sunday evening, Israel’s president, Reuven Rivlin, composed a prayer with which he called on Israelis and Jews worldwide to remember the pandemic’s victims in Israel — “those pioneers and founders, Holocaust survivors, veteran immigrants, fighters and creators, students of Torah and worshipers of the Lord, Jews and Arabs, old and young.”
“May we be forgiven for the sin of weakness and inability, for not doing enough, for not managing to save them,” Mr. Rivlin said. “Because of that, lives were lost.”