Characterization of CCP: Can We Use Past Convalescent Plasma from COVID-19 Patients for Treatment of New Emerging Variants?

Background and Objectives: New SARS-CoV-2 variants may impact the effectiveness of previously stored convalescent plasma (CCP). We defined levels anti-delta anti-omicron neutralizing antibodies (Nt-Abs) investigated possible differences past CCP Nt-Abs responses related to donor location in North South Italy. Methods: Serum from 153 donors recovered SARS-COV-2 infection (98 northern 55 southern Italy) were analyzed for characterization using our house microneutralization assay. Results compared anti-Spike IgG measured by chemiluminescent assay (CLIA) define a agreement with more affordable test. Results: delta titer comparison reference strain (PV10734 D614G) showed reduction 82% 77% Italy groups. Omicron 97%. corresponding > 1:80 median 1365 BAU/mL 653 strain. found no statistical between donors. Conclusions: Not all could be used treat patients omicron infections due lack specific Nt-Abs. For moment, neutralization test remains gold standard select potential Interestingly, study did not find NT-Abs collected living different areas