1. Main points
An estimated 96.6% of secondary school pupils and 62.4% of primary school pupils had coronavirus (COVID-19) SARS-CoV-2 antibody levels above the limit of detection in January to February 2022, after adjusting for sensitivity and specificity.
Antibody prevalence was significantly higher in Round 2 (January to February) than Round 1 (November to December) of the Schools Infection Survey (SIS) for both primary and secondary school pupils.
SARS-CoV-2 antibody prevalence continues to steadily increase by age for all pupils.
Over half of pupils aged four to seven 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 (January to February 2022)
Dataset | Released 1 April 2022
Initial estimates of pupils testing positive for SARS-CoV-2 antibodies from the COVID-19 Schools Infection Survey across a sample of schools. The Schools Infection Survey (SIS) is jointly led by the London School of Hygiene and Tropical Medicine, UK Health Security Agency, and the Office for National Statistics (ONS).
The Coronavirus (COVID-19) Schools Infection Survey (SIS) 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 (LSHTM) and UK Health Security Agency (UKHSA). Of note are:
Shamez Ladhani, Consultant Epidemiologist and Study Chief Investigator at UKHSA
Georgina Ireland, Senior Scientist at UKHSA
Punam Mangtani, Professor of Infectious Disease Epidemiology and Study Co-Principal Investigator at LSHTM
Patrick Nguipdop-Djomo, Associate Professor of Infectious Disease Epidemiology and Study Co-Principal Investigator at LSHTM
To account for the sensitivity and specificity of the oral fluid antibody test used, we apply an adjustment to results from unvaccinated pupils. Adjusted estimates are a more reliable indication of SARS-CoV-2 antibody positivity because unadjusted estimates underestimate the prevalence of SARS-CoV-2 antibodies in unvaccinated pupils when using oral fluid antibody tests. Adjustment for test accuracy is not necessary for vaccinated pupils. The test used is assumed to have 80% sensitivity and 99% specificity. For more information please see our COVID-19 Schools Infection Survey, 2021 to 2022: methods and further information article.
Antibody positivity is defined by having a fixed concentration of antibodies. A negative test result occurs if there are no antibodies, or if antibody levels are too low to reach a threshold at the time of testing. It does not mean that a person's antibody level is at zero or that they have no protection against coronavirus (COVID-19). Additionally, there are other parts of the immune system that will offer protection, for example, a person's T-cell response. This will not be detected by saliva tests for antibodies. A person's immune response is affected by factors such as health conditions and age.
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 COVID-19 Schools Infection Survey, 2021 to 2022: methods and further information article. We assess statistical significance using confidence intervals.
6. Measuring the data
Data presented in this bulletin are from Round 2 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 ethnicity, gender, and age.
See our COVID-19 Schools Infection Survey, 2021 to 2022: methods and further information article for 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 2021.
The results presented in this bulletin are from antibody tests conducted in schools in England between 10 January to 3 February 2022. This is referred to as Round 2.
In Round 2, 150 schools took part in testing (106 primary and 44 secondary). Within these schools, 7,664 pupils (4,119 primary and 3,543 secondary) took part in the COVID-19 antibody test. The total estimated response rate for participation in Round 2 antibody testing was 10%. The estimated response rate for primary school pupils was 15% and secondary school pupils was 7%.
More quality and methodology information on strengths, limitations, appropriate uses, and how the data were created is available in our COVID-19 Schools Infection Survey, 2021 to 2022: methods and further information 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.
Comparisons with the Coronavirus (COVID-19) Infection Survey
In our Coronavirus (COVID-19) Infection Survey (CIS), we also produce antibody estimates for pupils aged 8 to 11 years and aged 12 to 15 years. The CIS estimates that from 31 January to 6 February, 96.6% of children aged 8 to 11 years (95% credible intervals: 93.9% to 98.1%, sample size: 119) and 98.0% of children aged 12 to 15 years (95% credible intervals: 96.5% to 98.8%, sample size: 278) had antibodies to COVID-19 at the standard antibody threshold.
Compared with the SIS, the CIS uses a different antibody test (finger prick blood test) to determine antibody levels. It also has important differences in methodologies, including:
a slightly different sample population with a significantly lower sample size in this age group
data collection periods
While we estimate different levels of antibody positivity, both studies record a similar level of antibodies across the populations they cover. More information is available in our Using the COVID-19 School Infection Survey to measure the impact of the pandemic on children blog.Back to table of contents
7. Strengths and limitations
Please refer to the Strengths and limitations section of our previous COVID-19 Schools Infection Survey, England: pupil antibody data, November to December 2021.Back to table of contents
Contact details for this Statistical bulletin
Telephone: +44 1633 651663