Parents should be prepared for interruptions when schools return to in-person learning next week, the head of Ontario’s largest teachers’ union says.

“They should have a Plan B,” Elementary Teachers' Federation of Ontario president Karen Brown told Newstalk 580 CFRA on Tuesday.

“We know that we’re seeing mass disruption of school systems across America due to staff illness and isolation,” she told Ottawa at Work's Leslie Roberts. “What is going to happen when our members are ill and students are ill? Who’s going to be replacing our members?”

Ontario schools are reopening for in-person learning on Jan. 17, a government spokesperson confirmed Monday night.

The province delayed the return to school primarily to equip more classrooms with HEPA filters and send N95 masks for staff.

One local kindergarten teacher tells CTV News Ottawa she wants to be back in the classroom, but she's also worried about safety.

"I teach kindergarten, so I’m working with the youngest learners. With kindergarten, it’s a much more hands on program so it’s really important to actually be in a classroom. Virtual learning is definitely not the same," said Kim Thompson. "I’m not convinced I’m sure we’re ready to go back. Having said that, I know we need to go. It’s a difficult situation for everybody to be in."

Both of Ottawa’s English school boards have received shipments of masks.

The Ottawa Catholic School Board was one of the first to receive non-fit-tested N95 masks for staff. A spokesperson said Tuesday that 201,500 masks were delivered last week. Staff can choose to either wear N95s or medical masks. The province also supplied three-ply cloth masks for students that are available for free.

The Ottawa-Carleton District School Board was still waiting. As of last week, they were still waiting for 80 additional HEPA filters, though trustee Mark Fisher says many classrooms have them already.

"We’ve got HEPA filters in our highest risk needs areas of our board and our classrooms, we’ve got N95 masks in place, we’ve got the province providing three-ply masks which are different than what students are wearing, so I think when you put all these things together in addition to social distancing and some of those other measures, I definitely think over the last number of months and the last week we are making our schools much, much safer," he told CTV News Ottawa.

The Catholic board says all its schools already meet or exceed the province’s HVAC standards.

Education Minister Stephen Lecce said Tuesday that 9.1 million non-fitted N95 masks for staff and four million three-ply masks have been shipped so far.

He said in a statement the province is “deploying an additional 3,000 standalone HEPA filter units” to school boards, but did not say whether they had been shipped yet.

“We have been preparing for the return of in-class learning on Monday, January 17 by doing as much as we can to improve ventilation, provide high quality PPE and expand access to vaccinations,” he said.

Brown said the union has concerns about how safe schools will be given the rapid spread of the Omicron variant.

“If students are sick, learning is not going to occur, and if educators are sick it’s not going to occur,” she said. “It’s going to be interrupted. I think we need to take some time, do it right, and have a long-term plan.

“We want to return, but we want to return safely.”

Susan Gardner with the Ottawa-Carleton Elementary Teachers' Federation agrees.

"If things weren’t safe last week, what has changed in this very little amount of time?" she asked. "There’s definitely concern about returning so soon without assurances about any extra layers of protection."

The province is shifting how it handles testing and case tracking in schools ahead of next week’s return to the classroom.

Parents should no longer expect notifications for positive cases identified in their child’s classroom, according to a new provincial guidance document.

“Given the widespread transmission and inability to test all symptomatic individuals, schools will not be routinely notifying students/pupils in classes with a positive case, or if a child/student or staff is absent due to symptoms associated with COVID-19,” the guidance states.

Also, students will only be eligible for free PCR testing if they develop symptoms while at school. Last term, schools offered PCR self-collection kits to children with symptoms, those exposed to them and even the entire school population if an outbreak was declared.

Thompson says that she'd like the reporting of cases to continue.

"I wish they would keep the numbers being reported because it helps us to know for a potential outbreak," she said. "It just creates a lot of stress not knowing, and I think even as an adult who is very confident in their abilities and the whole situation, you can only tolerate so much. Not knowing creates more anxiety for a lot of people."

A concern echoed by Gardner.

"At this particular time, anyone in the class could potentially be a close contact or in fact have COVID and we just wouldn’t know. So I think that’s a real fear for people."

Lecce is scheduled to make an announcement on Wednesday about the preparations for returning to in-person learning.