Repeated Leftover Serosurvey of SARS-CoV-2 IgG Antibodies in Greece, May to August 2020

A serosurvey of IgG antibodies against SARS-CoV-2 was conducted in Greece between May and August 2020 It was designed as a cross-sectional survey and was repeated at monthly intervals The leftover sampling methodology was used and a geographically stratified sampling plan was applied Of 20,110 serum samples collected, 89 (0 44%) were found to be positive for anti-SARS-CoV-2 antibodies, with higher seroprevalence (0 35%) observed in May 2020 The highest seroprevalence was primarily observed in the “30–49” year age group Females presented higher seroprevalence compared to males in May 2020 (females: 0 58% VS males: 0 10%) This difference reversed during the study period and males presented a higher proportion in August 2020 (females: 0 12% VS males: 0 58%) Differences in the rate of seropositivity between urban areas and the rest of the country were also observed during the study period The four-month infection fatality rate (IFR) was estimated to be 0 47%, while the respective case fatality rate (CFR) was at 1 89% Our findings confirm low seroprevalence of COVID-19 in Greece during the study period The young adults are presented as the most affected age group The loss of the cumulative effect of seropositivity in a proportion of previous SARS-CoV-2 infections was indicated