Lester B. Pearson High School in Calgary now has two confirmed COVID-19 cases, which means an outbreak has been declared.
Alberta Health Services guidelines define an outbreak as two or more confirmed cases at the same school within 14 days.
In a message posted on the school's website, principal Kenneth Chee said the two cases at the school are separate "and no connection has been identified."
A letter from Alberta Health Services also posted to the school site, said its staff are working to determining who may have been exposed at the school.
"The risk of the general population in the school becoming infected because of these cases is low," reads the letter.
AHS says it will contact staff or students identified as a close contact of a confirmed COVID-19 case.
If staff or students develop symptoms, they should self-isolate at home and complete the online COVID-19 assessment tool or call 811 to arrange for testing, AHS said.
Later on Monday, an outbreak was also declared at Notre Dame High School in northeast Calgary.
On Sunday, an outbreak was declared at another Calgary school, Auburn Bay School in the southeast. The school serves Kindergarten to Grade 4 students.
As of Friday afternoon, when the province gave its latest COVID-19 update, 32 cases had been reported at 29 schools across the province. The figure wouldn't include Auburn Bay School, Lester B. Pearson High School or any other cases that emerged over the weekend, if any.
Three other Alberta schools had reported outbreaks as of Thursday afternoon — Henry Wise Wood High School in Calgary, St. Wilfrid Elementary in Calgary and Chinook School in Lethbridge.