The Niagara Catholic District School Board says that a person at Blessed Trinity Catholic Secondary School in Grimsby has tested positive for COVID-19.
They warn that students and staff may have been exposed to the virus while the person was contagious.
While in-person classes in Niagara are on hold, some schools are operating for students with special needs.
The person is currently in self-isolation.
Niagara Public Health is in the process of contacting students and staff who had direct contact with the individual.
Niagara Catholic is advising everyone to follow public health and safety guidelines put forth by Niagara Public Health.