SARS-CoV-2 antibody prevalence and symptoms in a local Austrian population

Ladage, Dennis; Hoeglinger, Yana; Ladage, Dorothee; Adler, Christoph; Yalcin, Israfil; Braun, Ralf

BackgroundSince December 2019 the novel coronavirus (SARS-CoV-2) is the center of global attention due to its rapid transmission and toll on health care systems and global economy. Population-based serosurveys measuring antibodies for SARS-CoV-2 provide one method for estimating infection rates and monitoring the progression of the epidemic. MethodsIn June 2020 we succeeded in testing almost half of the population of an Austrian township (n=835 of 1359 inhabitants) with a reported higher incidence for COVID-19 infections. We determined the level of prevalence for SARS-CoV-2 in this population, factors affecting, and symptoms correlated with prior infection. ResultsWe found a high prevalence of 9% positive antibodies among the town population in comparison to 6% of the neighboring villages. Only 20% of SARS-CoV-2 cases self-declared being asymptomatic. In contrast, we identified six single major symptoms, including anosmia/ageusia, weight loss, anorexia, general debility, dyspnea, and fever, and especially their combination to be of high prognostic value for predicting SARS-CoV-2 infection in a patient. Our comparison of the gold standard lab-based ELISA test and the on-site antibody test demonstrated a lack of accuracy for the latter test form. ConclusionsThis population study demonstrated a high prevalence of antibodies to SARS-CoV-2 as a marker of both active and past infections in an Austrian township. Several symptoms revealed a diagnostic value especially in combination. Results from self-administered antibody tests should be considered with caution.