St Vincent's University Hospital in Dublin has asked the public to avoid visiting patients unless absolutely necessary as staff try to curtail the spread of the winter vomiting virus.
According to a hospital statement, approximately 54 patients and 49 staff have been affected with the virus across 11 wards.
The hospital is also appealing to the public not to attend the Accident and Emergency Department if only complaining from the effects of the virus.
In the statement, the hospital said the visiting restrictions "are essential for the health and wellbeing of patients, visitors and staff and the hospital is appealing to all concerned to cooperate with the hospital".
