Limited window for donation of convalescent plasma with high live-virus neutralizing antibody titers for COVID-19 immunotherapy

Abstract Millions of individuals who have recovered from SARS-CoV-2 infection may be eligible to participate in convalescent plasma donor programs, yet the optimal window for donating high neutralizing titer COVID-19 immunotherapy remains unknown. Here we studied response trajectories antibodies directed surface spike glycoprotein and vitro live virus titers (VN) 175 donors longitudinally sampled up 142 days post onset symptoms (DPO). We observed robust IgM, IgG, viral neutralization responses that persist, aggregate, at least 100 DPO. However, there is a notable decline VN ≥160 therapy, starting 60 The results also show 30 years age or younger significantly lower VN, IgG IgM antibody than those older groups; with greater disease severity higher titers. Taken together, these findings define useful patients reveal important predictors an ideal donor.