An emergency doctor has highlighted the "red flags" that parents should look for if they think their baby could be infected with respiratory syncytial virus (RSV).
RSV is a very common and very contagious virus that causes cold-like symptoms initially but can lead to worrying complications in a small minority of cases.
Nearly all children will have had at least one infection of RSV by the age of two and for most it will cause a mild cold. However, it can develop into bronchiolitis or pneumonia.
Emergency medicine paediatric consultant Dr Carol Blackburn said children aged under three months are the most vulnerable.
The red flags parents should look out for are not feeding, vomiting after feeding and fewer than three wet nappies in a 24-hour period, a sign of dehydration.
If parents were concerned they should contact their family doctor, Dr Blackburn told RTÉ's Today with Claire Byrne.
While there had been a slight reduction in the number of cases in the past week, she said hospitals were still seeing a lot of cases.
At the end of October, Children’s Health Ireland reported a 50 per cent increase in the number of children attending their Emergency Departments in Temple Street, Crumlin and Tallaght and the Urgent Care Unit in Blanchardstown, compared to the same period in 2019, which was their busiest year on record.
This year was a tough winter for RSV, Dr Blackburn said, as usually the virus would peak in December but it varies from year to year.
However, she warned that there was still "a lot" of the virus about and it could continue "all the way" to February.
Dr Blackburn explained that young babies breathe through their nose and if that was blocked up then it caused problems with breathing and feeding and could lead to respiratory distress.
RSV was around every winter, she said, and it is a virus that "we live with in paediatrics".
Covid-19 lockdowns in 2020 meant she and her colleagues did not come across RSV. Continued hygiene measures meant there were fewer cases last year as well, but now toddlers were coming across the virus for the first time and were passing it on to younger siblings.
Dr Blackburn emphasised the red flags for parents to watch out for and added that a high temperature was not always an issue, and to be alert for dehydration, vomiting and not feeding. “These are the signs that parents should pick up on,” she said.