1. Main points
Round 4 of the study took place from 15 to 31 March 2021 shortly after schools in England reopened following the third coronavirus (COVID-19) lockdown; pupil antibody results are only available up to Round 2 (which took place in December 2020).
In March 2021 (Round 4), 21.52% of primary school staff (95% confidence intervals: 17.54% to 25.94%) and 18.66% of secondary school staff (95% confidence intervals: 16.47% to 21.00%) tested positive to SARS-CoV-2 antibodies.
The seroconversion rates (converting from negative antibody test to positive) between Round 1 (November) and Round 2 (December), and between Rounds 2 and 4 were similar for secondary school staff (5.4 and 5.0 respectively per 1,000 person-weeks).
For primary school staff, although the seroconversion rate was higher between rounds 2 and 4 compared with the rate seen between Rounds 1 and 2 (7.8 and 4.5 respectively per 1,000 person-weeks), this difference was not statistically significant.
In December 2020 (Round 2), 13.45% of secondary school pupils (95% confidence interval: 11.67% to 15.40%) tested positive to SARS-CoV-2 antibodies, this was significantly higher than primary school pupils at 9.05% (95% confidence interval: 7.33% to 11.00%); however, there was no significant difference in the seroconversion rate between primary and secondary pupils between November (Round 1) and December (Round 2).
Data presented are not intended to be generally applicable to all schools in England. The study was originally designed to oversample schools in areas of England where COVID-19 infection was highest at the start of the academic year (September 2020). Further information can be found in the methodology article.
The antibody tests used in this study detect antibodies produced following natural infection and not vaccination.
Have you been asked to take part in the study?
For more information, please visit the SIS participant guidance page.
If you have any further questions on the COVID-19 Schools Infection Survey (SIS), you can telephone IQVIA helpline on 0800 917 9679 or email firstname.lastname@example.org.
4. Staff vaccination rates
Staff vaccination data were obtained by linking to the National Immunisation Management System (NIMS). Details of the data matching can be found in our methodology article. Of the staff where immunisation status was available, 63.74% had received at least one vaccination before the end of Round 4 (31 March 2021).
Vaccination data by age and local authority results can be found in the accompanying dataset.
As our vaccination rates relate to school staff in 14 local authorities and are not generalisable to all school staff in England the data in this bulletin will differ from the administrative data on vaccinations published by NHS England weekly, which cover all vaccinations given to individuals who have an NHS number and are currently alive in the resident population.
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5. COVID-19 Schools Infection Survey data
COVID-19 Schools Infection Survey Round 4
Dataset | Released 27 May 2021
Initial estimates of staff and pupils testing positive for coronavirus (COVID-19) from the COVID-19 Schools Infection Survey across a sample of schools, within selected local authority areas in England.
The Coronavirus (COVID-19) Schools Infection Survey analysis was produced by the Office for National Statistics (ONS) in collaboration with our research partners at the London School of Hygiene and Tropical Medicine and Public Health England.Back to table of contents
A confidence interval gives an indication of the degree of uncertainty of an estimate, showing the precision of a sample estimate. The 95% confidence intervals are calculated so that if we repeated the study many times, 95% of the time the true unknown value would lie between the lower and upper confidence limits. A wider interval indicates more uncertainty in the estimate. Overlapping confidence intervals indicate that there may not be a true difference between two estimates. For more information, see our methodology page on statistical uncertainty.
A result is said to be statistically significant if it is likely not caused by chance or the variable nature of the samples. For more information, see our methodology page on statistical uncertainty.
8. Measuring the data
Data presented in this bulletin are from Round 4 (with comparisons with Round 1 and Round 2) of the COVID-19 Schools Infection Survey (SIS). These findings are from testing for antibodies to SARS-CoV-2 only. Results on current infection can be found in our bulletin published on 4 May 2021.
The results presented in this bulletin are from antibody tests conducted in schools in England between 15 and 31 March 2021 – referred to as Round 4 for staff, and antibody results for pupils between 30 November and 11 December 2020 – referred to as Round 2.
Round 3 was due to take place in late January 2021. Testing within schools for this round was cancelled because of schools in England being shut to the majority of pupils during lockdown.
As at 16 April 2021, in Round 4 of testing, 4,154 staff participated in at least one current COVID-19 infection or COVID-19 antibody test. This is around 35% of eligible staff in the sampled schools.
Prior to the commencement of Round 4, participation was offered to all year groups in secondary schools (excluding year 11) to improve the sample size; 42 out of the 80 secondary schools that took part in Round 4 testing had extended participation to other year groups. In Round 4 of testing, 11,033 pupils (3,762 primary and 7,271 secondary) participated in at least one current COVID-19 infection or COVID-19 antibody test. The estimated response rate for secondary school pupils, in the year groups that participation was offered to, was 17%. The estimated response rate for primary school pupils was 20%. Details of previous rounds response rates can be found in the accompanying dataset.
Further quality and methodology information on strengths, limitations, appropriate uses, and how the data were created is available in our methodology article.
Data cleaning and quality assurance is being carried out on data collected as part of the study on an ongoing basis. All estimates presented in this bulletin are provisional results. Estimates may therefore be revised in future publications.Back to table of contents
9. Strengths and limitations
Please refer to the Strengths and limitations section of the COVID-19 Schools Infection Survey, Round 2 bulletin.Back to table of contents
Contact details for this Statistical bulletin
Telephone: +44 (0)20 8039 0326