1. Main points
It is estimated that 82% of secondary school pupils and 40% of primary school pupils had coronavirus (COVID-19) SARS-CoV-2 antibody levels above the limit of detection in Round 1 of the COVID-19 Schools Infection Survey (SIS) during the academic year ending 2022, after adjusting for sensitivity and specificity.
Antibody prevalence was higher in secondary school pupils as most secondary school pupils testing positive for SARS-CoV-2 antibodies were vaccinated.
SARS-CoV-2 antibody prevalence steadily increased by age for all pupils.
A third (33.9%) of pupils aged 4 to 7 years tested positive for SARS-CoV-2 antibodies.
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, please email the SIS operations team: Schools.Studies.Mailbox@ons.gov.uk.
3. COVID-19 Schools Infection Survey, questionnaire and antibody data
COVID-19 Schools Infection Survey, antibody data, England
Dataset | Released 28 February 2022
Estimates from the Schools Infection Survey of pupils testing positive for SARS-CoV-2 antibodies. Including breakdowns by age, sex and region where possible.
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 UK Health Security Agency.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.
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 article.
6. Measuring the data
Data presented in this bulletin are from Round 1 of the COVID-19 Schools Infection Survey (SIS) during the academic year ending 2022. These findings are for SARS-CoV-2 antibodies for pupils only.
Estimates have been weighted and are representative of the pupil population in state-funded schools in England.
Our methodology article provides further information about response rates, survey design, how we process data and how data are analysed.
Age in this bulletin is calculated using the pupil's date of birth as of 31 August 2022.
The results presented in this bulletin are from antibody tests conducted in schools in England between 10 November and 10 December 2021 — referred to as Round 1.
In Round 1, 117 schools took part in testing (34 primary and 83 secondary); 5,972 pupils (3,183 primary and 2,789 secondary) took part in the COVID-19 antibody test. The total estimated antibody testing response rate for Round 1 was 10%. The estimated response rate for primary school pupils was 15% and secondary school pupils was 8%.
More 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
7. Strengths and limitations
The antibody assays (UKHSA Oral Fluids tests) used test oral fluid samples for IgG antibodies against SARS-CoV-2 nucleocapsid Protein (anti-N; from natural infection) and against SARS-CoV-2 Spike protein (anti-S; from natural infection or vaccination) allowing for a robust measurement of SARS-CoV-2 antibodies in school-aged pupils, which differs from the antibody test used in Schools Infection Survey (SIS) (academic year ending 2021), which measured antibodies following natural infection only.
The SIS is a longitudinal study and participants that do not withdraw after Round 1 will be invited to be tested for antibodies in future rounds. This will allow for comparisons to be made across different study rounds and help monitor the prevalence of antibody positivity over time. These results across different rounds will also provide an opportunity to present antibody conversion rates in future publications.
Pupils provide an oral fluid (saliva) sample as a non-invasive measure for testing for antibodies compared with a finger prick blood test, which is typically used to test for antibodies in adults. The anti-N antibody test is estimated to have an 80% sensitivity and 99% specificity for unvaccinated pupils compared with the finger prick blood test. Therefore, a statistical adjustment has been applied to our figures for unvaccinated pupils to account for this.
Antibodies following natural infection could fall below levels of detection faster than antibodies following vaccination. Therefore, some pupils that appear to have antibodies following vaccination only could have in fact have had antibodies following natural infection.
Test results are currently only available for those who had enrolled in the survey and were present in the school building on the day of testing.
Those absent from school on the day of testing for non-COVID-19 infection reasons were unable to participate in the testing round, and those with symptomatic infections and those self-isolating would not be included.Back to table of contents
Contact details for this Statistical bulletin
Telephone: +44 1633 651663