“…Long et al ., 2020; Seow et al ., 2020; Ward, Cooke, et al ., 2020; Choe et al ., 2021), single timepoint serology estimates may yield misleading insights into the true extent of CoV2 spread. We, therefore, aimed to investigate the evolution of the CoV2 seroprevalence in the canton of Zurich, a particularly low prevalence setting during the first and second waves in 2020, using an in-house developed tripartite automated blood immunoassay (TRABI) already employed in multiple studies (Cervia et al ., 2020; Emmenegger, Saseendran Kumar, et al ., 2021; Emmenegger et al ., 2022; Gehlhausen et al ., 2022; Schneider et al ., 2022). Continuous immunosurveys were conducted in a large cohort of the University Hospital of Zurich (n=55’814 samples) and blood donors from the Blood Donation Services of the canton of Zurich (n=16’291), over a period from December 2019 to December 2020, i.e.…”