The number of occasional teachers was already critically low before the pandemic.
But with class back in session in a COVID-19 world, new learning models across Waterloo Region, it presents a unique problem.
More classes will be taking place than last year due to distance learning and smaller class sizes.
"We actually were in a bit of a crisis before the real crisis happened," said Nathan Core, president for the local chapter of occasional elementary teachers with the Waterloo Region District School Board.
"We had seen what we call 'fail-to-fills,' or positions that had gone unfilled. Prior to the pandemic, we were in a shortage situation with occasional teachers."
Core believes that shortage will only be compounded this year, mainly because some occasional teachers fear a return to class.
For those teachers who don't rely on teaching as their main income, Core said he received significant calls voicing their intention to step back from the profession this year.
Core also noted that caution could lead to demand in another way.
"There used to be a time when a small sniffle or a cough, you might still stick it out, and make it into school to keep those students learning," he said, "I think those days are gone and I don't know when they'll ever come back."
There's a few factors that have led to the shortage, not the least of which was the Ontario government's change to the teachers college program to make it two years instead of one.
While that solved the oversupply of teachers (at the time), Core said the pendulum has swung the other way.
"I don't think there's going to be an easy solution to this, it's a big ship to steer," he said. "We're going to see some real issues with coverage for teachers."
Core admitted that the local boards have also been doing their best to get ahead of the problem, though it's proven to be a challenge.
As of Monday, the Waterloo Catholic District School Board was still looking to hire 24 teachers in elementary and 13 in secondary for distance learning.
The Waterloo Region District School Board is in the process of hiring an additional 90 elementary teachers and 30 Designated Early Childhood Educators for their distanced learning program as well.
"The board is going on a hiring spree, I've seen new member information coming out on an almost daily basis," said Core. "It does seem like they're doing everything they can to increase the numbers. They're between a rock and a hard place, because our teachers colleges are only pushing out so many members."