The ongoing evolution of SARS-Co-V2 variants to omicron severely limits available effective monoclonal antibody therapies. Effective drugs are also supply limited. Covid-19 convalescent plasma (CCP) qualified for high antibody levels effectively reduces immunocompetent outpatient hospitalization. The FDA currently allows outpatient CCP for the immunosuppressed. Viral specific antibody levels in CCP can range ten-to hundred-fold between donors unlike the uniform viral specific monoclonal antibody dosing. Limited data are available on the efficacy of polyclonal CCP to neutralize variants. We examined 108 pre-delta/pre-omicron donor units obtained before March 2021, 20 post-delta COVID-19/post-vaccination units and one pre-delta/pre-omicron hyperimmunoglobulin preparation for variant specific virus (vaccine-related isolate (WA-1), delta and omicron) neutralization correlated to Euroimmun S1 IgG antibody levels. We observed a 2-to 4-fold and 20-to 40-fold drop in virus neutralization from SARS-CoV-2 WA-1 to delta or omicron, respectively. CCP antibody levels in the upper 10% of the 108 donations as well as 100% of the post-delta COVID-19/post-vaccination units and the hyperimmunoglobulin effectively neutralized all three variants. High-titer CCP neutralizes SARS-CoV-2 variants despite no previous donor exposure to the variants.

Key points: All of the post-delta COVID-19/post vaccination convalescent plasma effectively neutralizes the omicron and delta variants.High-titer CCP and hyperimmunoglobulin neutralizes SARS-CoV-2 variants despite no previous donor exposure to the variants.