PT - JOURNAL ARTICLE AU - Ladage, Dennis AU - Harzer, Oliver AU - Winkler, Hannes AU - Knies, Andrea AU - Schneider, Miriam AU - Wagner, Robert AU - Engel, Peter AU - Frank, Wilhelm AU - Braun, Ralf TI - Persisting immune response to SARS-CoV-2 in a local Austrian population AID - 10.1183/13993003.congress-2021.PA3803 DP - 2021 Sep 05 TA - European Respiratory Journal PG - PA3803 VI - 58 IP - suppl 65 4099 - https://publications.ersnet.org//content/58/suppl_65/PA3803.short 4100 - https://publications.ersnet.org//content/58/suppl_65/PA3803.full SO - Eur Respir J2021 Sep 05; 58 AB - Background: Adaptive immune response to infection with SARS-CoV-2 comprises antibody response as well as T cell response. Population-based serosurveys provide a method for estimating infection rates and monitoring the response of the immune system to help elucidate population immunity.Methods: In June 2020 we tested 835 participants comprising almost half of the population of an Austrian township. We determined the seroprevalence of SARS-CoV-2, and symptoms correlated with prior infection. In two additional studies with patients recovering from COVID-19 in October and December 2020 we determined SARS-CoV-2-specific immunoglobulin A (IgA) and IgG levels (IgG), as well as specific T cell activities.Results: At baseline, 9% of our population tested seropositive for IgA (75/835) and IgG (71/835), respectively. We identified 6 major symptoms (anosmia/ageusia, weight loss, anorexia, general debility, dyspnea, fever), which in combination were of high prognostic value for predicting COVID-19 infections. In patients after COVID-19 infection at 4 months follow-up IgA and IgG levels were stable. At 6 months follow-up, 97% of previous COVID-19 cases tested positive for IgA, IgG or T cell activity with 63% testing positive for all of them. A lasting immune response was positively correlated with disease severity.Conclusions: We found a high baseline seroprevalence of SARS-CoV-2 infections in an Austrian township. Specific adaptive immune response remained detectable after 6 months in vast majority of patients recovering from COVID-19.FootnotesCite this article as: European Respiratory Journal 2021; 58: Suppl. 65, PA3803.This abstract was presented at the 2021 ERS International Congress, in session “Prediction of exacerbations in patients with COPD”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).