Population-based Age-stratified Seroepidemiological Investigation Protocol for Coronavirus 2019 (COVID-19) Infection in the Federation of Bosnia and Herzegovina

This study is the second cross-sectional study conducted in the region. In the first cross sectional study, conducted in the winter of 2020, we aimed to estimate the seroprevalence of SARS-CoV-2 IgG antibodies among blood donors in Sarajevo Canton. We also assessed immune durability among seropositive participants after 6 months. In total, of 1015 blood donors aged 18-65 years in Sarajevo Canton between 2 November and 3 December 2020 were recruited and population-weighted seroprevalence in Sarajevo Canton was 19.2% (95% CI: 16.7-21.6%). The aim of this second cross-sectional study is to measure the seroprevalence SARS-CoV-2 antibodies and assess antibody kinetics in the blood donor population after 12 months.