A Covid-19 outbreak at a school has directly affected about 20 staff and students.
It closed the school temporarily - the only one of 4,000 to be shut as a result of the disease since the new term began a month ago.
There were about 20 cases amongst staff and students linked to the outbreak, according to the HSE, which is still actively involved.
The school has since re-opened, with some restrictions to returns still currently in place.
Latest HSE figure show that cases of Covid have been detected in 140 of the country’s 4,000 mainstream schools since pupils returned.
Some 105 primary schools and 35 post-primary schools have undergone, or are undergoing, mass testing - one of the key public health responses when Covid-19 is identified in an education facility.
As well as that, Covid-19 has been identified in 39 childcare facilities and eight special education facilities, bringing the overall number of education settings where testing has been carried out to 187.
More than 4,455 students and teachers from the 187 settings, have, so far, undergone testing to check whether they had the disease.
The testing led to a further 87 cases being detected - 16 in childcare facilities, 49 in primary schools, 12 in post primary and 10 in special education facilities.
Confirmation of a Covid-19 infection in an educational setting triggers a Public Health Risk Assessment (PHRA) and determines what action is required.
Public Health professionals engage directly with the person, or family as appropriate, and asks them about their contacts. They also liaise with the school.
Recommended measures, including testing and asking other pupils or staff members to stay at home, are made at this point.
According to the HSE, responses and recommendations for each facility may differ, depending on the circumstances identified by Public Health.
In most cases, the follow-up action, in terms of testing and asking pupils and staff to restrict movements is confined to a class, or a pod - a small group of pupils within a class – or, at most, a class year.
According to the HSE, while multiple cases can be found in a school, categorisation as an outbreak – where two or more people are infected – as a result of in-school transmission, is only determined following an assessment.
“If multiple detected cases are found Public Health will review and determine if these are linked within the school setting. Multiple cases can be found in a school but not determined to be due to transmission within the school setting,” the HSE stated.
According to the most recent data from the Health Protection Surveillance Centre (HPSC) which monitors the spread of disease in Ireland, up to the midnight Saturday September 26, there have been 36 Covid outbreaks in schools, including 13 last week and 11 the previous week.
Where outbreaks occurred, the HPSC said transmission of Covid-19 within the school has not necessarily been established.
Risk of transmission within schools is considered to be low and health chiefs say it is more likely that children, or staff, would bring infection in from outside.
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