Seroprevalence studies have proved their worth in estimating the size and directionality of an outbreak of infectious disease, especially the current pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced coronavirus disease 2019 (COVID-19). A new study posted to the medRxiv* preprint server describes the prevalence of SARS-CoV-2 antibodies in five representative regions of Germany.