Visiting is being restricted at Dublin's Beaumont Hospital following an outbreak of the winter vomiting bug at the hospital.
The hospital has issued an urgent appeal to the public to refrain from any unnecessary visiting this weekend.
There are 52 patients who are displaying symptoms of the virus.
A total of 19 beds are currently closed in the wards affected.
Visiting restrictions were introduced following the start of the outbreak just over a week ago.
The outbreak spread rapidly and continues to affect the majority of wards.