A student at Fort Frances High School has been exposed to COVID-19.
School and health officials says they are taking steps to ensure all potential risks are minimized, including closing one classroom.
All other classes remain open.
Known contacts are being called and given instructions.
A close contact is considered someone who has been within 2 metres of another person for longer than 15 minutes.
Individuals passing by in a hallway are not considered contacts and have very minimal risk of spreading infection.
Meantime two classes at Dryden High School remain closed due to possible exposure to the virus.
However the health unit says there are no known cases at the school.
