TORONTO -- As students at Toronto elementary schools return to the classroom today for the first time since March, an uptick in COVID-19 cases in the province has prompted some concerned parents to switch to virtual learning at the last minute, TDSB Chair Alexander Brown said Tuesday.

On Monday, the TDSB confirmed that thousands of elementary students made the switch from in-person learning to virtual instruction just days before classes were set to begin, forcing the school board to delay the start of its virtual program to Sept. 22.

The number of students making the switch to online classes, Brown said, is continuing to grow as COVID-19 cases rise in Ontario.

"As the numbers start to creep up, I guess we all start to worry more. I guess this is one of the reasons we saw a shift back to virtual. Maybe some parents were fearful and they want to wait and see where we are in a week or two and I get that," Brown said on Tuesday morning.

"As the numbers go up, this is where the province needs to step in and make sure that we can ensure that our schools remain safe."

Ontario reported a spike in new COVID-19 infections on Monday, with 313 new cases confirmed over a 24-hour period.

That number dipped down to 251 today but is still considerably higher than the daily cases reported just last week.

The TDSB said 66,000 students were initially enrolled in virtual school, a number that has ballooned to more than 72,000 since last Friday.

TDSB spokesperson Ryan Bird confirmed that an additional 1,500 students have switched to virtual learning in the past 24 hours and officials are still trying to work out the logistics.

“It is just the staffing around trying to plan for more than 73,000 kids, which would really equate to the total enrolment of most Ontario school boards,” Bird said. “It really is massive.”

The TDSB said an additional 200 teachers are needed to accommodate the recent increase in virtual enrolment.

Carlene Jackson, the interim director of education for Canada’s largest school board, said she expects the number of students switching to online learning will continue to rise before today’s 4 p.m. deadline.

After today, anyone who wishes to change to either in-person instruction or virtual learning must wait until after Thanksgiving.

“We can't do it at any given point throughout the year because it does mean reorganizing schedules,” she said.

TDSB working to lower class sizes to 'targeted caps'

The TDSB has promised to keep class sizes for in-person learning capped at 26 for students in junior and senior kindergarten, 20 for students in grades one through three, and 27 for students in grades four through eight. At schools in neighbourhoods with higher rates of COVID-19 infection, class sizes for students in grades four to eight are supposed to be capped at 20.

Bird said some schools are still working to bring down class sizes to the targeted caps.

“When it comes to larger class sizes, we are going to putting in resources to make sure those are lowered back down,” he told CP24 on Tuesday.

“We are making sure teachers are assigned so we can lower those class sizes back down to where our targeted caps are to make sure that we are not seeing 34, 35. That is not acceptable to us.”

Many teachers in the province have been critical of the Ford government’s decision not to decrease the size of elementary school classes to a level that would allow for appropriate physical distancing.

Some have said that providing even the epidemiologically-recommended minimum of one-metre of distancing between desks in some classrooms would be challenging if not impossible.

Infection control protocols have been put in place at schools in an effort to prevent the virus from spreading and at the TDSB, students in all grades are required to wear masks.

High school students at the TDSB, who will be attending in-person instruction on alternating days, will return to the classroom on Thursday.

“The timetabling for our high school students is really a substantial process for both virtual and in-person so a lot of this work is continuing this week,” Bird said.

“We have had a successful start to the school year with our staggered elementary start and we will continue on next week.”