Burton Borough School updated parents today, advising them that Year 9 children should stay away from school for the rest of the week.
Over the weekend, the school sent a letter to families advising an outbreak had been identified, with 144 students and four members of staff told to self-isolate.
An update today confirmed that all of Year 9 will be told to stay home.
"We have unfortunately had to make the decision to close the whole of the Year 9 bubble due to operational reasons," said the update.
"The number of positive cases in the Y half have been rising (we now have five altogether), with the majority of Year 9 X half students having to isolate as well. As a school, we would highly recommend that your child stays at home where possible and contacts are minimised.
"Should we receive any further positive cases that affect your child, we will inform you as soon as possible and ask them to isolate.
"As it currently stands, all students in Year 9 will return to school on Monday, May 10. All lessons from tomorrow will revert to being online on Teams.
"We really appreciate your understanding as we know that this decision may be of inconvenience. Any decision we make is with the Health Protection Hub and we will continue to work with them for the rest of the bank holiday and the coming week."