RESUMEN
Understanding the coronavirus (CoV) antibody landscape in relation to disease and susceptibility is critical for modelling of steps in the next phase during the current covid-19 pandemic. In March 2020, during the first month of the epidemic in The Netherlands, we performed cross sectional studies at two time points amongst patients of the Erasmus Medical Centre in Rotterdam, to assess the presence of antibodies against seasonal human coronaviruses (OC43, 229E, NL63, HKU1), emerging zoonotic coronaviruses (SARS, MERS) and SARS-CoV-2 in nine different age groups. We observed minimal SARS-CoV-2 reactivity early March (0.7% of sera), increasing to 3.0%, four weeks later, suggesting probably undetected cases during this early phase of the epidemic. Antibody responses were mostly coronavirus species specific at young age, but possible cross-reactivity between human seasonal CoVs was observed with increasing age.