KITCHENER -- Health officials have declared an outbreak of COVID-19 in a student cohort at Elmira District School.

The outbreak was declared Thursday after a student told to self-isolate earlier in the week tested positive for the disease.

Earlier this week, officials said a student at the school had tested positive for COVID-19 and two student cohorts were told to self-isolate as a result.

Some more transportation students are now self-isolating after the case identified on Thursday. No staff members have been affected.

Officials say the outbreak is only in one cohort.

This is the second COVID-19 outbreak declared at a Waterloo Region public school this week. The first was at Clemens Mill Public School.