Highly Potent SARS-CoV-2 Neutralization by Intravenous Immunoglobulins manufactured from Post-COVID-19 and COVID-19-Vaccinated Plasma Donations

From September 2020, some immunoglobulin lots from US plasma contained neutralizing antibodies against the newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Paralleled by the increasing numbers of post- coronavirus disease 2019 (COVID-19) donors, immunoglobulin lot antibody positivity increased to 93% by January 2021, at a mean titer of approximately 30 IU/mL. The correlation predicted that anti-SARS-CoV-2 potency would reach 345 IU/mL by July 2021. In addition to post-COVID-19 donors, the rapidly increasing number of plasma donors vaccinated against COVID-19 resulted in a mean antibody titer of >600 IU/mL in July 2021 immunoglobulin lots, with SARS-CoV-2 antibody titers for several lots even higher than those of earlier produced hyperimmune globulin products.