Institut de Recherche Expérimentale et Clinique;
Department of Epidemiology and Biostatistics;
Faculty of Public Health;
Université Catholique de Louvain;
Brussels;
Belgium;
Pediatric Infectious Diseases;
Pediatric Department;
CHU Liège;
Liège;
Belgium;
Pediatric Infectious Diseases;
Specialized Pediatric Service;
Pediatric Department;
Cliniques Universitaires Saint-Luc;
Brussels;
Belgium;
Department of Pathology;
Erasme University Hospital;
Université Libre de Bruxelles (ULB);
Hô Universitaire de Bruxelles (HUB);
CUB Hô Erasme;
Brussels;
Belgium;
Institut de Recherche Expérimentale et Clinique;
Université Catholique de Louvain;
Brussels;
Belgium;
Department of Microbiology;
Cliniques Universitaires Saint-Luc;
Brussels;
Belgium;
Office de la Naissance et de L’enfance;
Brussels;
Belgium;
SARS-CoV-2; CHILDREN; SCHOOLS; SEROPREVALENCE; Socioeconomic Status; Belgium;