Three year groups at a performing arts academy are self-isolating after a Covid-19 outbreak.
Around 85 positive cases have been recorded at the Wilkes Academy in Swindon, the "vast majority of which are students", it said.
Face-to-face teaching was suspended last week after there was a confirmed case.
Principal Nikki Wilkes said "full support" was being offered to the students affected.
The academy said it took the decision to isolate three year groups so the "risk to the wider community is low".
Ms Wilkes said it has been "actively monitoring Covid-19 case numbers across the Wilkes community".
She said it would "continue to implement a range of planned, increasing measures" to reduce the risk of the virus spreading.
Steve Maddern, from Swindon Borough Council, said it was in regular contact with the academy to "provide advice" and help it "manage and contain this outbreak".
"We appreciate this current outbreak will generate some anxiety among Swindon residents, but it is important to recognise that as cases and contacts are currently self-isolating the risk of broader community transmission is low," he said.
The academy, based in west Swindon caters for around 270 students - aged 16 to 19 - from across the country.