There have been confirmed Covid-19 cases in half of Northern Ireland's schools since the start of term.
That is according to new figures published by the Public Health Agency (PHA).
The PHA has been informed of 2,030 positive Covid cases in schools since teaching returned at the beginning of term.
There had been 608 Covid-19 so-called incidents in 519 schools up until 20 October, said the agency.
2,030Positive Covid cases in schools
519Schools with at least one positive Covid case out of 1,035 total schools
302Schools with a single positive case
237Schools with a cluster of two to five cases
69Schools with a cluster of more than five cases
An incident can be a single positive case, a cluster of two to five cases or more than five cases.
A cluster is defined by the PHA as two or more laboratory-confirmed cases of Covid-19 among individuals in one setting, such as a school.
This is the first time the agency has reported the number of Covid cases specifically in schools.
In other Covid-19 developments on Friday:
- Seventeen more Covid-19 related deaths were recorded by NI statistics agency Nisra until last Friday (16 October), bringing its death toll to 930
- Five more deaths and 1,252 were recorded by the Department of Health
- Trauma surgery at Craigavon Area Hospital may have to be rationed if Covid admissions continue to put pressure on services, a surgeon has warned
- Shop owners in NI have spent more than £10m on Covid-19 safety measures, such as plastic screens and hand sanitiser, since the pandemic began
The figures from the PHA detail the number of cases in schools from the start of term in late August up until Tuesday.
They show that:
- 302 schools had a single positive case - 228 primaries, 59 post-primaries and 15 special schools
- 237 schools had a cluster of two to five cases - 136 primaries, 88 post-primaries and 13 special schools
- Sixty nine schools had a cluster of more than five cases - nine primaries, 55 post-primaries and five special schools
A school can have more than one Covid "incident"- for instance, it could have two separate cases or clusters that are not linked to each other.
Overall, 86% of post-primary schools had at least one case since the start of term, compared to around 40% of primary schools and 66% of special schools.
Around three-quarters of schools (76%) in the Belfast City Council area have been affected by positive cases.
That local government district had the highest proportion of schools affected, just higher than the numbers recorded in Londonderry, Strabane and Omagh - the district with the second highest proportion.
Of school cases notified to the PHA, just over two-thirds (68%) were pupils and one-third (32%) were staff.
The PHA does not report how many pupils or staff had to self-isolate as a result of coming into contact with positive cases in schools.
However, separate figures released to the Alliance MLA Chris Lyttle in response to an assembly question showed that over one in 10 teaching and non-teaching staff were not working in school in the week from 6-13 October.
Just over a third of those staff were absent from school as they were self-isolating for 14 days.
However, staff who are self-isolating may still be working from home.
Some schools have been forced to close for short periods and teach pupils online, due mainly to a number of staff self-isolating.
Schools in Northern Ireland began an extended two-week half term break on Monday 19 October.