Follow-up study in the ski-resort Ischgl: Antibody and T cell responses to SARS-CoV-2 persisted for up to 8 months after infection and transmission of virus was low even during the second infection wave in Austria

Wegene Borena, Zoltan Banki, Katie Bates, Hannes Winner, Lydia Riepler, Annika Roessler, Lisa Pippberger, Igor Theurl, Barbara Falkensammer, Hanno Ullmer, Andreas Walser, Daniel Pichler, Matthias Baumgartner, Sebastian Schönherr, Lukas Forer, Ludwig Knabl, Reinhard Würzner, Dorothee von Laer, Jörg Paetzold, Janine Kimpel

Research output: Working paper/PreprintPreprint

Abstract

BackgroundIn early March 2020, a SARS-CoV-2 outbreak in the ski resort Ischgl in Austria initiated the spread of SARS-CoV-2 throughout Austria and Northern Europe. In a cross-sectional study, we found that the seroprevalence in the adult population of Ischgl had reached 45% by the end of April. To answer the question of how long immunity persists and what effect this high-level immunity had on virus transmission, we performed a follow-up study in early November, 2020. MethodsOf the 1259 adults that participated in the baseline study, 801 could be included in the follow-up. The study involved the analysis of binding and neutralizing antibodies and T cell responses. In addition, the incidence of SARS-CoV-2 infections in Ischgl was compared to the incidence in similar municipalities in Tyrol throughout 2020. FindingsFor the 801 individuals that participated in both studies, the seroprevalence declined from 51.4% (95% confidence interval (CI) 47.9 - 54.9) to 45.4% (95% CI 42.0 - 49.0). Median antibody concentrations dropped considerably but antibody avidity increased. T cell responses were analysed in 93 cases, including all 4 formerly seropositive cases that had lost antibodies in all assays, three of which still had detectable T cell memory. In addition, the incidence in the second COVID-19 wave that hit Austria in November 2020, was significantly lower in Ischgl than in comparable municipalities in Tyrol or the rest of Austria. InterpretationThis study has important implications as it shows that although antibodies to SARS-CoV-2 declined, T and B cell memory can be detected for up to 8 months. Complemented by infection prevention measures a level of around 40-45% immunity in Ischgl significantly reduced local virus transmission during the second wave in Austria in November 2020. FundingFunding was provided by the government of Tyrol and the FWF Austrian Science Fund.
Original languageEnglish
DOIs
Publication statusPublished - 2021

Publication series

NamemedRxiv
PublisherCold Spring Harbor Laboratory Press

Keywords

  • epidemiology

Fields of Science and Technology Classification 2012

  • 303 Health Sciences

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