Previously, anyone who was in a classroom with an infectious case was considered a close contact and required to self-isolate.

The health minister said on Thursday that each person testing positive has about 11 contacts. 

Alberta Premier Jason Kenney says he has tested negative for COVID-19 but will continue to self-isolate after a close contact, Municipal Affairs Minister Tracy Allard, received a positive test result Wednesday.

When someone tests positive for COVID-19, a contact tracer is assigned to their case by the local public health authority. They ask questions to get an idea of who the infected person has been around.