Characterization of 100 sequential SARS‐CoV‐2 convalescent plasma donations

BACKGROUND: Transfusion of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) convalescent plasma is a promising treatment for severe coronavirus disease 2019 (COVID-19) cases, with success of the intervention based on neutralizing antibody content. Measurement by serologic correlates without biocontainment needs as well as an understanding of donor characteristics that may allow for targeting of more potent donors would greatly facilitate effective collection. STUDY DESIGN AND METHODS: One hundred convalescent plasma units were characterized for functionally active SARS-CoV-2 neutralizing antibodies, as well as for SARS-CoV-2 binding antibodies, with the intention to establish a correlation between the functionally more relevant neutralization assay and the more accessible enzyme-linked immunosorbent assay (ELISA). Donor demographics such as COVID-19 severity, age, and sex were correlated with antibody titers. RESULTS: = 0.5386). A tendency of higher-titer plasma units from donors with increased disease severity, of advanced age, and of male sex was seen, yet the functional relevance of this difference is questionable. CONCLUSION: The ELISA-based correlation to neutralization titer enabled a threshold proposal that could be used to eliminate lower-titer units from the clinical supply for COVID-19 treatment. Disease severity may be associated with the development of higher titers of neutralizing antibodies, although larger case numbers will be needed for additional confirmation.