The Windsor-Essex County Health Unit can't give an exact number, but estimates over 600 students have been dismissed since the start of the school year because of COVID-19.
The number does not include daycare centres across the region. There have been dismissals from those facilities too.
The majority do not have a confirmed case but had close contact with an infected student.
On the Windsor-Essex Catholic District School Board website, a list of confirmed active cases shows 12 students and one staff member have the virus. A total of 16 classes at nine elementary and secondary schools have been sent home.
The Greater Essex County District School Board's website does not say how many classes are impacted but does confirm eight active infections at eight different schools, all involving students.
Provided by the Windsor Essex County Health Unit.
Health Unit CEO Nicole Dupuis said 17 classes in all have been dismissed at both boards so far.
She said she's not surprised by the number of students, although she admitted it is higher than expected.
"We had a lot of dismissals last year," said Dupuis. "We were prepared there would be quite a large impact."
Since those under the age of 12 are not yet eligible to get a COVID-19 vaccine, and the vaccination rate among those in their teens is still around 50 per cent, Dupuis said
She said the health unit recommended a delay to the start of extracurricular activities in school to make it easier for staff to monitor the spread of the virus in schools.
"We wanted to be able to monitor the situation before we introduced other activities that will increase dismissals, increase exposures throughout the school," explained Dupuis.
While some schools have multiple cases, the health unit has not declared an outbreak at any.
At the Greater Essex County District School Board, cases are confirmed at:
* Bellewood Public School * Queen Victoria Public School * Sandwich West Public School * West Gate Public School * Westview Freedom Academy Public School * Herman Academy - Secondary * Leamington District Secondary School * Sandwich Secondary School
The Windsor-Essex Catholic District School Board reports cases at:
* Stella Maris Catholic Elementary School * St. John de Brebeuf Catholic Elementary School * St. Pius X Catholic Elementary School * St. John Vianney Catholic Elementary School * L.A. Desmarais Catholic Elementary School * St. Joseph's Catholic High School * Cardinal Carter Catholic Secondary School * F.J. Brennan Catholic High School * St. Anne Catholic High School
On Tuesday, public health officials reported 45 new cases of COVID-19, of which 19 are close contacts of someone the virus that the health unit is already tracking. Another six people caught it in the community, and the origin of 20 other infections is still under investigation.
The number of active cases in Windsor-Essex has dipped to 455, while 20 people are in the hospital.
There were also two new deaths, a man in his 70s and another in his 80s who lived in the community. That brings the death toll since March 2020 to 448.
There are 22 outbreaks in the region. Nineteen of them are in workplaces, one is in a long-term care or retirement home, and two are in the community.