The highly contagious norovirus has affected a number of residents at Donisthorpe Hall and caused the Leeds home to postpone a major fundraiser.
Some 180 guests were expected at a brunch this Sunday, including civic dignitaries.
Event organiser Regina Waldman said: “We have an outbreak of the winter vomiting virus at the home and in the interests of residents, staff and the wider community we are left with no alternative but to postpone.”
Donisthorpe Hall chairman Andrew Brown rued a lost opportunity “to demonstrate to guests our amazing dementia facilities.” The brunch has been rescheduled for March.
The virus can be transmitted through contact with an infected person or contaminated surfaces and objects. As a precaution, the home has restricted visiting and social and cultural activities.