Parents are being advised to keep sick kids at home next week as the winter flu strain is affecting children from babies up to 15-year-olds.
Of the 592 patients waiting on trolleys in hospitals today, 12 are children.
Fewer than 10 people have died of flu so far this winter but at least 190 people have been hospitalised with the illness.
Assistant National Director of Health Protection at the HSE, Dr Kevin Kelleher said anyone with flu-like symptoms should stay at home.
"We want to make sure it is not spread. Going back to work or school when you've got symptoms will spread it," he said.
"Flu spreads very easily - particularly in closed things like classrooms or workspaces," he added.
"If your child has the symptoms, please don't send them to school. Look after them at home. Likewise, if you've got the symptoms - don't go into work," he added.