We’ve known this was coming for weeks, and the New York City Department of Education knew also. Or at least they should have. Mayor Bill de Blasio issued a mandate for all teachers and school staff in the city to be vaccinated by midnight three days ago. Those failing to comply would be out of work starting this morning. The initial numbers coming into the New York Post indicate that the levels are pretty much as predicted. Nearly 4,000 substitute teachers were required for classes today, along with a larger, unknown number of non-teaching workers. And despite assurances from City Hall that there are more than enough substitute teachers to go around, there were still classrooms without instructors and generous offers for more substitute (vaccinated) teachers were being sent around.

The city Department of Education is looking to plug nearly 3,700 openings for substitute teachers as the COVID-19 vaccine mandate for public school staffers goes into effect Monday, The Post has learned.

The 3,659 vacancies amount to an average of about two subs per each of the system’s roughly 1,800 schools — though the needs at some schools, including in Brooklyn and Queens, are far greater, according to an email sent Saturday and obtained by The Post.

The starting dates for the fill-in gigs range from Monday to May 2022, though the bulk of the roles begin in October, according to the email sent to the pool of public school substitute teachers.

There probably are enough substitute teachers to cover all of the openings, at least for the time being. But the problem is that they are not all equally dispersed around the metropolitan area in the places where they are needed. Schools that only need the projected one or two substitutes seem to be able to find them. But other, larger schools with a dozen or more sudden vacancies are apparently not finding enough subs within reasonable commuting distance.

This brings us back to the aforementioned lack of planning. As recently as last week, Mayor Bill de Blasio was insisting that the vaccine mandate was going to go into effect and there would be enough vaccinated personnel to cover all of the gaps. But clearly, nobody went to the trouble of doing the math and making sure that the subs would be ready and available at the places where they would actually be needed. So just when New York parents thought things were getting back to normal and in-person learning was going to move forward, the system is thrown back into chaos once again. And this is not a problem being caused by the virus. This is a problem created by City Hall that could have been staved off if they’d actually thought all of this through.

Meanwhile, the now unemployed teachers are still out in the streets marching for the right to return to their jobs if they provide a negative COVID test, as other municipal employees are allowed to do. Here’s some video of all that fun.

“Let us teach!” chants from the crowd at today’s march against New York’s vaccine mandate #NewYork pic.twitter.com/GD8LBET8lr

— Brendan Gutenschwager (@BGOnTheScene) October 4, 2021

Exit questions: Knowing what we already know about the availability of fake COVID documentation of all sorts and the many people who have already been caught using such forgeries, how many of the teachers who “beat the vaccination deadline” just last week are actually vaccinated? How many obtained a fake CDC card? And could the people at the schools responsible for checking such things actually be able to tell the difference? If the answers to any of these questions remain unknown, then this is all simply more pandemic theater.