Over 40 per cent of students were absent from one school in the city today.
Principal Aaron Wolfe from Coláiste Éamann Rís says over 180 students stayed at home today because of Covid reasons.
Schools across the country returned to the classroom this morning after the Christmas break, with warnings from teaching unions that some schools would find it difficult to hold classes as normal.
The ASTI says up to four and half thousand secondary school teachers are out today due to Covid-related absences.
Speaking to RedFM News, Aaron Wolfe says other schools in the city and beyond are seeing similar rates of absenteeism:
"From talking to other principals in other schools, they're largely say the same thing. We have 41% of our student population absent today. So that's a huge number of students that are missing education. They're out of the system. They're not being taught. They are at home. And it a mix between people that are close contact or they have Covid. So they could be out of the education system now for 10 days or so. There's no provision to teach those students because classes are going on in school. So it is a very strange day, particularly when half of your students are missing."