KITCHENER -- Four local students, two in high school and two in elementary school, have tested positive for COVID-19.

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In an announcement on Monday, the Waterloo Region District School Board said that the high school student, who attends Huron Heights Secondary School, was last in the building on Sept. 17.

One of the elementary student goes to Williamsburg Public School. They were last in the school on Sept. 18. The other goes to Clemens Mills Public School in Cambridge. The student was in the building on September 14 and no high-risk contacts have been identified. 

There is also a confirmed case at Forest Heights Collegiate Institute, the school board confirmed on Monday evening. That person was last at school on Sept. 15.

Public health officials haven't identified any high-risk school contacts associated with the case.

The school board said high-risk contacts from both cases are being contacted, and that public health officials will provide individual guidance to them.

Those identified as being high-risk at Huron Heights will be asked to self-isolate until at least Oct. 1, and maybe longer if they become symptomatic. For Williamsburg contacts, they should self-isolate until Oct. 2.

"If you are not contacted by Region of Waterloo Public Health, your child is not considered a high-risk contact," the announcement read in part.

Acting Associate Medical Officer of Health Dr. Julie Emili said public health officials are working with the school board to contact high-risk contracts.

All students in the class at Huron Heights are self-isolating and will need to get tested, according to Dr. Emili.

"We do not require contacts of contacts to isolate," Dr. Emili said. "Isolation would come into play if the contact became symptomatic."

Two other students, one each in the public and Catholic school boards, have also tested positive, as has a staff member at a WRDSB school.

Waterloo Region has seen an uptick in cases this month, going from 42 active cases on Sept. 1 to more than 110 on Sept. 21. The total number of cases in the region has surpassed 1,600.

Ontario also continues to report more cases, setting a months-long high in new cases Monday with 425. That's the highest single-day increase since June 2.