Fig. 1

Study description. a Timeline of the surveys conducted in the study area since the start of the SARS-CoV-2 epidemic in Vo’. b Flow chart illustrating the study design, which focuses on the subjects who were found to be positive early in the pandemic (from February 2020 to May 2020, according to the ground truth definition). The serosurveys were conducted in Vo’ on three time points, 1st–3rd May 2020, 28th–29th November 2020, and 5th June 2021