The ski trip took place during half-term and was to Aprica in Northern Italy.
The school says it is following Coronavirus advise from Public Health England.
They have advised that the isolation is for 6 days, until 1 March 2020. The isolation only applies to those that went on the trip and does not extend to family or others that have come into contact with them.
The school says it will remain in close contact with those involved and will be undertaking deep-cleaning of the school on a daily basis.
Harrogate Grammar had a group of students return from Folgarida in Northern Italy, but are following different advice. They have taken advice from the Director of Public Health at North Yorkshire County Council and from Public Health England. They are following a guidance that those that have returned from Northern Italy should only self-isolate if they show symptoms.
Nationally at least three schools in the UK have closed and others told pupils to self-isolate – we don’t have the exact figure.