Just five days into the school year for most of the province, schools are reporting 189 active cases of COVID-19 among students and staff, dozens of classes are self-isolating at home and one school is completely closed.

And schools in the Greater Toronto Hamilton Area were reporting 74 of those cases Monday, with hundreds of students already ordered home to self-isolate due to exposures.

The Toronto District School Board (TDSB) leads the region with 20 known cases as of Monday morning, spread across 18 schools. Toronto Public Health also said late Monday that there were 23 investigations underway at schools in the city.

“It is not unexpected that we’ve started to see COVID-19 cases in our school settings as we continue living with this virus. Vaccination continues to be our best defense against this virus. It provides protection for those receiving the vaccine and for others around them," Medical Officer of Health Dr. Eileen de Villa said in a press release. "This is why we continue to remind everyone who is eligible to get vaccinated as soon as they are able if they have not yet done so.”

Elsewhere in the GTHA, the Halton Catholic District School Board has found seven cases and ordered three classrooms to self-isolate at home and seek testing.

In Hamilton, the Hamilton-Wentworth Catholic District School Board is reporting 10 active cases of COVID-19 and local public health officials have ordered 12 classrooms of students to self isolate at home due to exposure.

On Sunday night, GTHA boards were reporting only 50 new cases.

This year, vaccinated students and staff will not need to self-isolate in the event of an exposure if they do not develop symptoms consistent with COVID-19.

But right now, the province is not publicly disclosing COVID-19 cases confirmed among the province’s roughly 2 million students and 300,000 education workers.

An online portal updated daily last year is currently dormant, left publicly visible only for “archival and research purposes.”

An official in Education Minister Stephen Lecce’s office told CP24 the portal will be restarted in the next few days, and was dormant only to allow school boards to get their own reporting processes up and running.

Last year at this time, many schools had not resumed operations, but of those that were conducting in class instruction across the entire province, there were just 15 known active cases.

Across the remainder of the province, a count of data from school boards found 115 cases as of Monday morning.

And Viscount Alexander Public School in Cornwall, Ont. became the first of the province’s 4,800 public schools to close due to COVID-19 this school year, after officials announced an outbreak there on Sunday and ordered all students and staff to go to remote learning for at least one week.

The Ministry of Education released a comprehensive plan for school reopening in August, with loosened restrictions on some activities and an emphasis on increasing ventilation and air quality indoors, as public entities slowly adopt the idea that the coronavirus is airborne.

But parents on social media have shown that classes in multiple school boards are larger than what board-wide class-size averages say they should be.

One parent in the GTA showed a class with 40 pupils in it.

Lecce has said he doesn’t want widespread school closures like what dominated the 2020-2021 school year, instead preferring localized, isolated closures.