The cause of a respiratory infection which resulted in the hospitalisation of several students of a Co Kildare secondary school this week is still unknown.
The school, Naas CBS, which closed at lunchtime on Thursday to prevent the spread of the virus, is expected to reopen on Monday.
However, its principal, Mr Noel Merrick, said yesterday this would depend on developments over the weekend.
A small number of pupils had presented to their GPs with fresh symptoms of the infection yesterday, he said. Cleaning staff at the school worked yesterday to disinfect surfaces "as a precautionary measure".
Tests on water samples taken from the school on Thursday showed there was no difficulty with the water supply.
About 20 students from the 800-pupil boys' school were admitted to Naas General and Tallaght Hospitals with sore throats and high temperatures.
Mr Merrick said seven of the 17 students admitted to Naas Hospital were discharged yesterday, and by last night those in Tallaght Hospital had also been discharged.
The Eastern Regional Health Authority's department of public health and the local area health board have advised anybody with a sore throat, temperature and cough to take paracetamol, drink plenty of fluids and stay at home. If they are worried or begin to feel worse they should contact their GP.
Initially it was feared the boys might have had meningitis, but tests ruled this out.