An entire kindergarten class at an Upper Beaches elementary school is self-isolating after a student tested positive for COVID-19.

In a letter sent to parents, Heather Groves, the principal of Bowmore Road Junior and Senior Public School, confirmed the positive case.

"As a result of this case, (Toronto Public Health) has asked the affected class at our school to self-isolate for a period of 14 days as a precaution. As TPH had no similar concerns for the remainder of the school, only the parents/guardians of the students in the impacted classes were informed as per our protocols," the letter read.

She said the school is working closely with Toronto Public Health in responding to the situation.

"TPH will continue to provide advice and communication to those directly affected and/or the school community as necessary," the letter read.

"As per our procedures, staff and students are required to wear masks while at school and practice physical distancing, as well as proper hand hygiene (hand washing, sanitizer, etc.). As a precaution, an enhanced cleaning will be conducted in the impacted areas."

The Toronto District School Board confirms that the 20 students who are self-isolating are all members of the same junior/ senior kindergarten class.

There are currently 78 TDSB schools reporting active COVID-19 cases with 66 cases involving students and 29 involving staff.

Ten schools are reporting two or more cases and one school has been shut down.

Five cases have been confirmed at Martingrove Collegiate Institute, a TDSB secondary school in Etobicoke. 

The school remains open despite the positive cases.

"We take our lead from Toronto Public Health so the TDSB will not arbitrarily close a school. We have to rely on the medical experts," TDSB spokesperson Ryan Bird told CP24 on Friday. 

"Toronto Public Health has determined at this point that there is no transmission within the school and it is the transmission within the school that really prompts an outbreak declaration or even a possible closure."