SARS-CoV-2 Sero-Surveillance in Greece: Evolution over Time and Epidemiological Attributes during the Pre-Vaccination Pandemic Era.

Background: Nation-wide SARS-CoV-2 seroprevalence surveys provide valuable insights into the course of the pandemic, including information often not captured by routine surveillance of reported cases.

Methods: A serosurvey of IgG antibodies against SARS-CoV-2 was conducted in Greece between March and December 2020. It was designed as a cross-sectional survey repeated at monthly intervals.

Factors associated with IgG positivity to Crimean-Congo hemorrhagic fever virus in the area with the highest seroprevalence in Greece.

In order to gain insight into the factors playing a role for the high seroprevalence of Crimean-Congo hemorrhagic fever virus in the human population of Thesprotia prefecture, Greece, serum samples were collected from residents of the area together with a questionnaire about demographic and epidemiological factors. A 14.4% seroprevalence was detected, with increased age, agro-pastoral activities, slaughtering, and contact with animals (especially sheep) among the factors associated with seropositivity.