TY - RPRT T1 - Prevalence and incidence of antibodies against SARS-CoV-2 in children and school staff: Main findings of the fourth testing period among primary schoolchildren (Sep-Oct 2021) Y1 - 2021 A1 - Joanna Merckx A1 - Mathieu Roelants A1 - Milena Callies A1 - Ines Kabouche A1 - I Desombere A1 - Els Duysburgh KW - Belgium KW - CHILDREN KW - COVID-19 KW - SARS-CoV-2 ER -