The highest ever incidence of the respiratory virus RSV was recorded in Ireland last week.
According to the Health Protection Surveillance centre, 368 people were hospitalised due to the illness last week, and a total of 985 cases were reported.
In a statement, the HSE urged the public to protect children and newborns - noting the very high levels in Ireland, especially in those aged four and under.
It warned the virus is usually more serious in children.
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