An entire high school year group has been told it must self-isolate for the next two weeks after a pupil tested positive for coronavirus.
All Year 7 pupils at Lliswerry High School in Newport have been told to stay home for the next 14 days.
Newport council said 185 children at the school are affected, and were sent home on Tuesday after the positive Covid-19 result was revealed.
The school said “home learning will be provided for all Year 7 learners”.
In a letter to parents, head teacher Neil Davies said: “Unfortunately, we have had a confirmed case of Covid-19 with one of our learners in Year 7.
“This means that in line with guidance from Welsh Government and Newport City Council all children in that year group cannot be in school and need to self-isolate for 14 days.”
Officials said a “focused clean” is taking place at the school, which has over 800 pupils.
“All other year groups will continue to attend school as planned. There is no need for anyone who is not contacted to self-isolate or be unduly concerned,” added the school’s head.
In a statement, Newport council said it had procedures across the city to “limit group numbers and pupil contact, coupled with enhanced cleaning regimes”.
“School staff remain vigilant to pupils displaying any symptoms, and are ready to take appropriate action,” said a council official.
“Parents, carers and guardians can support this by remaining alert and ensuring that children do not attend school if they develop any potential symptoms, however mild.”
There have been 33 cases of Covid-19 recorded in the Newport council area in the last seven days, which is a rate of 21.3 per 100,000 people.
It comes as the neighbouring authority of Caerphilly enters a second day of enhanced lockdown measures, following a spike in coronavirus cases across the county borough.
There have been 151 cases of the virus over the last week in Caerphilly, with a rate of 83.4 per 100,000 – the highest in Wales.
How many schools have been affected by Covid-19?
Across Wales, hundreds of pupils have been sent home to self-isolate as a precaution since the autumn term started last week.
At least 11 schools have been forced to take action, in nine local authorities.
It includes more than 200 pupils at Bryntirion Comprehensive in Bridgend, who were ordered home after coming into contact with a person who tested positive.