Late last week and through the weekend, Peel saw significant increases in case counts and the spread of variants in the community.
"TPH will continue to recommend early dismissal for individual schools upon investigation to protect students, staff, teachers, and school communities", said the health unit Monday.
Dr. Lawrence Loh says he is ordering schools in Brampton, Caledon and Mississauga to close starting tomorrow.
Peel Region's top doctor says he has ordered all schools to be closed.
As of Wednesday, all students will pivot to remote learning for the rest of the week, according to the Toronto District School Board.
Education Minister Stephen Lecce announced last week that Ontario schools would remain open for in-class learning after the scheduled April spring break, despite calls from teachers' unions that continuing to work unvaccinated in classrooms is too risky.
The TDSB and TCDSB said in tweets on Monday they are dismissing the schools following advice from TPH.
Further decisions to extend Section 22 will be made, as required, and TPH says the return date for in-person learning will be re-evaluated and is subject to change.
Ontario reported 236 new, school-related COVID-19 cases on Tuesday, including 207 in students.
"The health and safety of students and staff remains a priority for TPH".
"This closure is a necessary step to protect staff and students in Peel Region", Dr. Lawrence Loh said in a statement, exercising his discretionary powers to enact such closures under Section 22 of the Ontario Health Protection and Promotion Act.
Dubey added: "COVID-19 spreads through close contact with someone who is infected with the virus, and not from specific locations".
"TPH will continue to manage risk on a school-by-school basis, taking immediate and appropriate action to address these complex outbreaks", it said in a statement.
Students also need to wear a mask that fits well when outside their homes, wash their hands often and stay home if they are sick.