Up to 12,000 children are out of school due to being close contacts of confirmed Covid-19 cases, according to the Health Service Executive (HSE).
Several thousand additional children are also off classes as they have contracted the disease or were not sent to school after a positive diagnosis, according to The Irish Times.
About 1,200 schools in the State have now identified a case among students as they return to classrooms for the new academic year.
HSE head of testing and tracing Niamh O’Beirne said an average of 15 children are identified as close contacts in primary schools and three in secondary schools, where physical contact is less common.
Close contacts cannot return to school until they receive a clear PCR test result on day 10 after being designated as contacts. Siblings of a confirmed case, as they have a continued exposure risk, cannot resume classes until they get a clear PCR test after 17 days.
Covid-19 cases have been identified in about 700 primary schools and 500 secondary schools, meaning 10,000 to 12,000 children are affected as close contacts.
Ms O’Beirne said children who are restricting their movements have a “relatively low likelihood of being positive”.
It is estimated at least 1,200 children who were in school have been confirmed as having the disease and are off school, and about 2,800 contracted the virus but have not resumed school.
Ms O’Beirne has said the high demand for testing among school-based close contacts reflected the level of Covid-19 in the community, rather than evidence of spread within schools.
She added that demand for swabbing in the community is at its strongest since early this year, during the third wave, but that positivity is not climbing. There were 20,500 swabs taken in the community by 5pm on Monday.