Pupils and staff at Ullswater Community College have been sent home to self isolate after a student was diagnosed with COVID-19.
Between 10 and 12 families and eight to 10 members of staff have been affected, according to Cumbria County Council.
A spokesman for the council said: “We are aware of it and we have been working with the school.
“People for who it is necessary to self isolate as a result of the case are doing so, but there is just one positive case which has been diagnosed.”
Head Stephen Gilby said 10 students and three members of staff were affected.
“We can confirm that a student at UCC has tested positive for COVID-19,” he said.
“This was a random test on the student and their family, none of whom displayed symptoms at any time; the student had been in attendance at school.
“We were able to quickly implement our well-planned procedure, which complies with government and PHE recommendations.
Ten students who may have been in close proximity to the student have been required to isolate for 14 days, as have three members of staff who were also in close contact.
“The school and the remaining students have been able to operate in line with our adjusted arrangements following the return from lockdown.
“Let me take this opportunity to thank all the members of our community for their continued support; in particular the students, who continue to impress with their mature and responsible approach to these challenging times.”