Persisting antibody response to SARS-CoV-2 in a local Austrian population

Ladage, Dennis; Roesgen, Delia; Schreiner, Clemens; Ladage, Dorothee; Adler, Christoph; Harzer, Oliver; Braun, Ralf

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic. The prevalence and persistence of antibodies following a peak SARS-CoV-2 infection provides insights into the potential for some level of population immunity. In June 2020 we succeeded in testing almost half of the population of an Austrian township with a higher incidence for COVID-19 infections. Now we performed a follow-up study to reassess the prevalence of SARS-CoV-2-specific IgA and IgG antibodies. In 121 people, including 68 participants of the previous study we found the prevalence of IgG and IgA antibodies remaining remarkably stable with 84% of our cohort prevailing SARS-CoV-2-specific antibodies, which is only a slight decrease from 93% four months before. Most patients with confirmed COVID-19 seroconvert, potentially providing immunity to reinfection. Our results suggest a stable antibody response that we observed for at least six months post infection with implications for developing strategies for testing and protecting the population.