KITCHENER -- Officials working in Waterloo Region schools are urging people to follow public health orders as more classes show up in local classrooms.

Paul Gladding, the principal at St. John Catholic Elementary School, posted a YouTube video begging people not to gather.

"We are really in a difficult situation for our school community," he said in the video. "You cannot be having birthday parties, gatherings or dinners, and even going to church at this time can bring you into contact with all kinds of people."

The school has the highest case count ever seen in a Waterloo Region school with at least a dozen cases. It closed last week due to a staffing shortage. An outbreak has also been declared at the school.

In his video, Gladding said teachers have concerns about students not self-isolating.

"They have seen other kids around, hanging around with a sibling that they on-camera," he said. "Those folks are definitely not keeping a six-foot distance at home and they are not wearing masks in most cases."

Loretta Notten, the director of education at the Waterloo Catholic District School Board, said she's aware of around 15 cases at the school. Public health has reported 12.

"Some of the cases are connected to spread at the school," Notten said. "We also have a number of families where it's siblings that are connected."

The school is located in an area identified as a high-priority neighbourhood by public health officials, due to high rates of community spread. There are pop-up COVID-19 testing sites at Victoria Hills and Kingsdale Community Centres.

The WCDSB said the centres will be used for targeted testing this week.

"That will take in Resurrection High School St. John, St. Dominic Savio and, I believe, St. Pauls," Notten said.

Public health officials said the pop-up testing sites were there to help improve accessibility, adding the pandemic has had a greater impact on residents who are visible minorities and living in lower income households.

St. Johns remains closed to in-class learning until March 8.

The Waterloo Region District School Board said three classes at Sunnyside and five at Howard Robertson Public Schools were dismissed due to COVID-19 cases. Both schools are in areas with targeted testing available.

In a statement, the school board said officials are monitoring the staffing situation at both schools closely.