On Sept. 23, 2021, Council of School Supervisors and Administrators President Mark Cannizzaro said that it was "dangerous and irresponsible" for the city to move forward with implementing the vaccine mandate for staff on Sept. 27 because it would leave schools severely understaffed. Cannizzaro called on the city to delay the deadline for the mandate.

In response, UFT President Michael Mulgrew issued the following statement: 

The principals’ union is right — our schools are not ready for the implementation of the vaccine mandate. I hope for once City Hall is listening to its own school leaders and finally starts to put together a reasonable plan to face the challenge of keeping our children safe.