CORRECTION: European Cohorts of Patients and Schools to Advance Response to Epidemics (Eucare): a Cluster Randomised Interventional and Observational Study Protocol to Investigate the Relationship Between Schools and Sars-Cov-2 Infection (Bmc Infectious Diseases, (2023), 23, 1, (1), 10.1186/S12879-022-07947-6)