The world is confronting Coronavirus Disease-2019 (COVID-19) pandemic caused by SARS-CoV-2 virus, which is causing many deaths and burden on intensive care facilities. Data regarding epidemiologic characteristics in children and young adults is limited, especially in the context of educational settings. Due to mild symptoms or even asymptomatic cases in children, the rate of SARS-CoV-2 infected children is underestimated. Therefore, the present study aims to determine the incidence of SARS-CoV-2 infection in children at 3 timepoints during 12 months expressed as seroconversion measured in non-invasive saliva sampling in Tübingen, a defined study area. Children and adolescents (N = 1850) in the age of 1 to 17 years will be recruited via child-care, kindergarten and primary and secondary schools and followed-up for 12 months: shortly after release of lock-down measures in summer 2020, before winter and after the winter. An adult cohort (adult comparator group) is sampled at the same time points for incidence comparisons. To validate the ELISA for SARS-CoV-2 antibody measurements in saliva compared to blood, and to understand the half-life of SARS-CoV-2 antibodies in respective body fluids, peripheral blood and in saliva will be sampled every 2 months in an additional adult group (adult validation group).
