To help schools manage wider opening we have published guidance for schools including how any suspected or confirmed cases of COVID-19 should be handled:
Where a child or staff member tests positive, the rest of their class or ‘bubble’ should be sent home and advised to self-isolate for 14 days. The other household members of that wider class or group do not need to self-isolate unless the child, young person or staff member they live with in that group subsequently develops symptoms. Closure of the school itself will generally not be necessary where the school is observing guidance on infection prevention and control which will reduce the risk of transmission.
As part of the national test and trace programme, if other cases are detected within the cohort or school, a Public Health England local health protection team will conduct a rapid investigation and will advise the school on the most appropriate action to take.