"Figure 5: The percentage of pupils testing positive for antibodies to COVID-19 increased by age group ","" "Adjusted percentage of pupils testing positive for antibodies to COVID-19 by age group, England, January to February 2022 ","" "","" "Notes"," 1. Figures have been adjusted to account for the sensitivity and specificity of the antibody tests for unvaccinated pupils. 2. After adjustment, estimates for pupils aged 12 to 15 years are greater than 99%. 3. Age is calculated using the pupil's date of birth as of 31 August 2021." "Unit","percentages" "","" "","Percent testing positive","Lower 95% confidence interval","Upper 95% confidence interval" "4 to 7","54.9","51.4","58.4" "8 to 11","74.0","71.4","76.5" "12 to 15","99.0","98.5","99.7"