WATERLOO -- As thousands of unvaccinated Ontario students could face stricter isolation rules when school resumes in September, Guelph's top doctor says vaccination status will be a factor when outbreaks are declared.

This fall, the vaccine status of students 12 to 17 will be a factor in an outbreak.

"If you're unvaccinated you will be required to have two tests, seven days apart. You will be required to go home and if one of those tests becomes positive, again you have to add on to that another 10 days," said Wellington-Dufferin-Guelph's medical officer of health, Dr. Nicola Mercer.

Those who are fully vaccinated and test negative can return right away. Dr. Mercer expects the same protocols for fully vaccinated students and staff.

"There will be differences and those differences will be hard to hide," she said. "Children that show up the next day for school will be the vaccinated, the fully vaccinated."

Mercer said while vaccine status is private, it will be noticeable when school starts.

"There may also be other requirements for other things, so extracurricular activities, the potential for choirs and bands and athletics," she said.

The Catholic teachers' union is calling on the Education Minister to provide guidance on vaccination policies as soon as possible.

"If there's going to be rules around this, let's make them standard, let's make them very public and make sure everybody is on the same page with this so that we'll know what the playbook is," said local president Patrick Etmanski.

Ontario's school boards have been able to ask for a student's immunization record for other disease under pre-pandemic legislation.

"But right now with the COVID vaccine, I'm not sure what the legalities around asking about vaccine," said Cathy Abraham with the Ontario Public School Boards' Association.

Dr. Mercer said the health unit has access to this information through Ontario Health when doing case and contact management.