Determination of neutralising anti-SARS-CoV-2 antibody half-life in COVID-19 convalescent donors

Barnes, Thomas W.; Schulte-Pelkum, Johannes; Steller, Laura; Filchtinski, Daniel; Jenness, Robin; Williams, Michelle R.; Kober, Christina; Manni, Sandro; Hauser, Thomas; Hahn, Aaron; Kalina, Uwe; Simon, Toby L.; Schuetz, Patrick; Roth, Nathan J.

Despite the burgeoning field of coronavirus disease-19 (COVID-19) research, the persistence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralising antibodies remains unclear. This study validated two high-throughput immunological methods for use as surrogate live virus neutralisation assays and employed them to examine the half-life of SARS-CoV-2 neutralising antibodies in convalescent plasma donations made by 42 repeat donors between April and September 2020. SARS-CoV-2 neutralising antibody titres decreased over time but typically remained above the methods' diagnostic cut-offs. Using this longitudinal data, the average half-life of SARS-CoV-2 neutralising antibodies was determined to be 20.4 days. SARS-CoV-2 neutralising antibody titres appear to persist in the majority of donors for several months. Whether these titres confer protection against re-infection requires further study and is of particular relevance as COVID-19 vaccines become widely available.