There have been 608 Covid-19 incidents at schools in the north, data shows.
A total of 519 schools - 373 primaries, 202 post-primaries and 33 special schools - had either a case or a cluster of cases up to October 20.
Half of the 1,000 schools in the north have had at least one Covid-19 case in a pupil or member of staff.
The majority of incidents (302) refer to a single positive case, while 237 had a cluster of two to five cases, and 69 had more than five.
The numbers were recorded by the Public Health Agency (PHA).
Schools were closed from March in an effort to stem the spread of the virus and reopened on August 24.
Schools report incidents of the virus to the PHA.
The highest proportion of incidents (76%) were reported in the Belfast City Council area.
A PHA bulletin reported receiving notification of 2,030 confirmed cases of Covid-19 in schools since August 24.
The data indicates that around 68% were pupils.
Last week Education Minister Peter Weir told the Stormont assembly that almost 1,500 cases had been identified in Northern Ireland's schools since they reopened to October 13.
Mr Weir said the figure represented a very small proportion of the school population of 333,000 pupils and 19,000 staff.
Schools are closed for an extended half term break as Northern Ireland battles a second spike of cases.
The PHA bulletin also said that by October 18, there had been 28,197 laboratory-confirmed cases of the virus.
Females (53%) account for marginally more cases than males and the Derry and Strabane council area continues to have the highest case rate at 776 per 100,000 of the population.
