Mr. de Blasio, a Democrat with less than a month left in office, has longstanding political ties to the ultra-Orthodox community and has faced criticism over his handling of issues including oversight of yeshivas and a circumcision ritual, metzitzah b’peh, that led to multiple babies becoming infected with herpes.
Mr. de Blasio has relied on ultra-Orthodox leaders as he has moved through the political ranks, rising from the City Council to become public advocate and then mayor. He also relied on Orthodox donors during his unsuccessful presidential campaign.
Mr. de Blasio announced the vaccine mandate for public schoolteachers in August, but he did not set a similar mandate for private schools. Some private schools have set their own mandates for teachers and students.
Dr. Thomas Chadzutko, the superintendent of the Diocese of Brooklyn’s schools, signed on to the letter with Rabbi Zwiebel. At Catholic schools in Brooklyn and Queens, the vaccination rate for teachers and staff members is about 88 percent, his spokesman said.
The letter argued that the mandate could be “devastating to our schools and the children they serve” if teachers who are not vaccinated lose their jobs during the middle of the school year.
“Some schools may even be forced to close because of the severe shortage of teachers,” it said.
In August, Cardinal Timothy M. Dolan, the archbishop of New York, said in a television interview that he was “highly encouraging” teachers and staff members at Catholic schools to get vaccinated, adding that employees who were not vaccinated had to submit to weekly testing.
“We can’t jeopardize the health of the kids,” he said.
A vaccine deadline for correction officers — which Mr. de Blasio had pushed back by a month because of the ongoing staffing crisis at the Rikers Island jail complex — arrived this week, and about 82 percent of uniformed staff at the Correction Department were vaccinated as of Thursday, city officials said.
Still, hundreds of officers were being put on unpaid leave, and many who have been vaccinated were working 12-hour shifts at jails.