Public Health England has published its study into Covid-19 transmission in primary schools in the summer half term. The findings are encouraging. Of 12,026 pupil/staff participants in 131 schools, just six tested positive. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/914700/sKIDs_Phase1Report_01sep2020.pdf

Of these six, three were negative when re-tested. The remaining three were two staff and one pupil. The pupil was asymptomatic, and the child of a healthcare worker who had previously tested positive.

After adjusting for missing staff/pupils, PHE estimated 3.9 cases per 100,000 pupils per week, and 11.3 cases per 100,000 staff per week. Where the positive cases were found it “did not find any additional cases within the household, class bubble or wider education setting”.

PHE concluded “infection and transmission rates were low in preschool and primary schools under surveillance”, and that chances of students and pupils having Covid-19 antibodies were “not associated with school attendance during the lockdown”.

Caveats- study carried out after lockdown easing when transmission at lowest & schools only partly open. "Our findings cannot be extrapolated
to senior schools, because the risk of.. exposure, asymptomatic
infection & symptomatic disease in teenagers is likely to be different"