Covid-19 School Infection Survey study

This research used data made available via the Office for National Statistics (ONS) Secure Research Service, which is being expanded and improved with ADR UK funding.

Authors: Public Health England, Office for National Statistics, The London School of Hygiene & Tropical Medicine

Date: May 2021

Research summary

Analysis using ONS data has helped assess the role of schools in coronavirus transmission. The evidence suggests that transmission rates have remained low while schools are open. The study has found no statistical difference between secondary school staff testing positive for coronavirus antibodies and the wider working-age population. Encouragingly, a dip in overall coronavirus cases for staff and pupils is evident following the return to schools in March 2021 compared with the Autumn 2020 term.

The coronavirus (Covid-19) pandemic has meant almost all school settings have experienced partial closures due to public health measures. This has resulted in months of missed education and affected the mental health and wellbeing of children and young people. By providing half-termly bulletins estimating the prevalence of Covid-19 infections and the incidence of antibodies against the virus, the School Infection Survey has sought to understand how transmission rates from and within schools can be minimised.  

Data used

The School Infection Survey investigates the prevalence of Covid-19 infections and the presence of antibodies to Covid-19 among pupils and staff within a sample of primary and secondary schools in England. Three rounds of data have been collected: Round 1 between 3 – 20 November 2020, Round 2 between 30 November – 11 December 2020 and Round 4 between 15 – 31 March 2021. Round 3 was cancelled due to the third national lockdown. Using a stratified, multi-staged sample design, the School Infection Survey concentrated on schools in ‘high-prevalence’ areas – defined by Covid-19 rates at the beginning of the academic year 2020-21.

All participants (pupils and staff) provide a nose swab to test for a Covid-19 infection. To test for Covid-19 antibodies, staff provide a finger prick blood sample and pupils provide a saliva sample. Socio-demographic data is collected through participant questionnaires, while headteacher questionnaires provide information on school-level implementation of protective measures to limit the spread of Covid-19. While caution is needed when interpreting the test results due to the small sample size, the data is a valuable asset in understanding the prevalence of Covid-19 infection within school settings.

Methods used

Rapid analysis of the survey is conducted after each round to provide quick insight into transmission among pupils and staff. ONS bulletins have been released concerning data collected in November and December 2020 and March 2021 so far. As the study oversamples schools in ‘high-prevalence’ areas, it is not designed to be generalised to all schools in England. Instead, data is weighted to make participating pupils and staff more representative of their wider local authority population. Weighting takes into consideration the design of the samples and reflects response patterns. Weighting continues to be used within the School Infection Survey bulletins and the procedure is continuously refined.

Research findings

Analysis from all three rounds of the School Infection Survey suggests schools had low rates of Covid-19 transmission. No statistical difference was found for positive tests of Covid-19 between Round 2 school staff data and the wider working-age population in their local authority. In Round 2, the majority of secondary schools (91%) had implemented at least 12 of 15 strongly recommended measures within Department for Education guidance, such as maintaining social distancing, using face coverings and enhanced cleaning.

Round 4 analysis suggests a decrease in positive tests for secondary school pupils and staff following the return to school in March 2021, compared with the Round 1 and 2 results. Round 4 found only 0.34% of secondary school pupils and 0.19% of secondary school staff tested positive for Covid-19.