German federal-state-wide seroprevalence study of 1st SARS-CoV-2 pandemic wave shows importance of long-term antibody test performance
Stefan Lohse, Anna Sternjakob-Marthaler, Paul Lagemann, Jakob Schöpe, Jürgen Rissland, Nastasja Seiwert, Thorsten Pfuhl, Alana Müllendorff, Laurent S. Kiefer, Markus Vogelgesang, Luca Vella, Katharina Denk, Julia Vicari, Anabel Zwick, Isabelle Lang, Gero Weber, Jürgen Geisel, Jörg Rech, Bernd Schnabel, Gunter Hauptmann, Bernd Holleczek, Heinrich Scheiblauer, Stefan Wagenpfeil, Sigrun Smola
Abstract
Background: Reliable data on the adult SARS-CoV-2 infection fatality rate in Germany are still scarce. We performed a federal state-wide cross-sectional seroprevalence study named SaarCoPS, that is representative for the adult population including elderly individuals and nursing home residents in the Saarland. Methods: pandemic wave steady state period. We selected an antibody test system with maximal specificity, also excluding seroreversion effects due to a high longitudinal test performance. For the calculations of infection and fatality rates, we accounted for the delays of seroconversion and death after infection. Results: Using a highly specific total antibody test detecting anti-SARS-CoV-2 responses over more than 180 days, we estimate an adult infection rate of 1.02% (95% CI: [0.64; 1.44]), an underreporting rate of 2.68-fold (95% CI: [1.68; 3.79]) and infection fatality rates of 2.09% (95% CI: (1.48; 3.32]) or 0.36% (95% CI: [0.25; 0.59]) in all adults including elderly individuals, or adults younger than 70 years, respectively. Conclusion: The study highlights the importance of study design and test performance for seroprevalence studies, particularly when seroprevalences are low. Our results provide a valuable baseline for evaluation of future pandemic dynamics and impact of public health measures on virus spread and human health in comparison to neighbouring countries such as Luxembourg or France.