About 80 students went on the trip to Piedmont last week. They have now been sent home from school as a precaution. There were also 10 teachers on the trip, who are also self-isolating.
There are 11 quarantined towns in northern Italy and Public Health England has issued guidance stating that anyone who has been to this area and has symptoms that can be associated with coronavirus should self-isolate at home and avoid contact with other people.
The Grammar School ski trip was to the north-western area of the country
'The children were sent home because the trip was to an area of northern Italy near to the locations where that have been confirmed cases of COVID-19,' a States of Guernsey spokesperson has said.
'Public Health Services is aware that at least one returning student is currently showing the relevant symptoms and will be tested for coronavirus.'
The rest of the students will be isolated at home until the test results come back.
Public health director Nicola Brink said: 'The relevant symptoms for a coronavirus - cough, fever, shortness of breath - are common to many winter illnesses which are frequently seen at this time of year.
The risk to the children and staff attending this ski trip is currently considered to be low and our actions at this stage are precautionary.'
All children who have been sent home today will be contacted by Public Health Services for further advice.
Director of Operations for Education, Ed Ashton, said: 'We have been working closely with colleagues from Public Health, who in turn have been in regularly contact with the Grammar School and Sixth Form Centre headteacher. Public Health are the experts and lead agency and therefore it is essential to follow the advice they have provided. We fully support the precautionary action they have asked the school to take.'
Currently 13 islanders have been tested for the illness and 12 have come back negative.
Self-Isolation advice, and other advice relating to COVI-19 can also be accessed here: www.gov.gg/coronavirus.
More in Wednesday's Guernsey Press.