Dr Sumi Dunne urged parents to keep their children at home if they are unwell, unless they only have a runny nose.
“If you feel your child is unwell, particularly if they suddenly develop a high temperature, a new cough, please keep them at home,” Dr Dunne said.
“Don’t dose them with paracetamol, don’t dose them with ibuprofen and send them into school.”
But she said that children can have persistent runny noses, which “can sometimes last a prolonged period of time”.
“In that instance if the child is well, and they are not having a temperature, there is no reason why they cannot go to school, or why they cannot attend preschool or creche,” she said.
Dr Dunne made the comments at the Department of Health briefing on Monday.
Many primary and secondary schools are reopening their doors to staff and students this week following six months of closure.
Dr Dunne said she appreciated that parents may be worried about their children returning to school and she advised them to contact their GP with any concerns that they may have.
In an open letter to parents, guardians, teachers and school staff, the country’s acting chief medical officer Dr Ronan Glynn said he was “very aware” of their worries.
He said their concern was natural and to be fully expected given the challenges posed by Covid-19, but he added that the decision to reopen the schools had not been taken lightly.
“If all of us continue to make small changes to the way we live, we can – together – starve this virus of opportunities to transmit,” Dr Glynn wrote.
“While it is okay to send your child to school or childcare if they only have a runny nose or a sneeze, if you have any concerns that your child has symptoms of Covid-19 – fever, cough, shortness of breath, loss of taste or smell – then please keep them at home until you have spoken with your GP by phone.”