SARS-CoV-2 Neutralizing Antibody Titers in Convalescent Plasma and Recipients in New Mexico: An Open Treatment Study in COVID-19 Patients

Bradfute, Steven B; Hurwitz, Ivy; Yingling, Alexandra V; Ye, Chunyan; Cheng, Qiuying; Noonan, Timothy P; Raval, Jay S; Sosa, Nestor R; Mertz, Gregory J; Perkins, Douglas J; Harkins, Michelle S

BACKGROUND: Convalescent plasma (CP) is a potentially important therapy for coronavirus disease 2019 (COVID-19). However, knowledge regarding neutralizing antibody (NAb) titers in donor plasma and their impact in acute COVID-19 patients remains largely undetermined. We measured NAb titers in CP and in acute COVID-19 patients before and after transfusion through the traditional FDA IND pathway. METHODS: We performed a single-arm interventional trial measuring NAb and total antibody titers before and after CP transfusion over a 14-day period in hospitalized patients with laboratory-confirmed severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection. Trial Registration: Clinicaltrials.gov identifier: NCT04434131 (https://clinicaltrials.gov/ct2/show/NCT04434131) RESULTS: NAb titers in the donor CP units were low (<1:40 to 1:160) and had no effect on recipient neutralizing activity one day after transfusion. NAb titers were detected in 6/12 patients upon enrollment and in 11/12 patients during at least two timepoints. Average titers peaked on day 7 and declined towards day 14 (P=0.004). NAb and IgG titers were correlated in donor plasma units (ρ=0.938, P<0.0001) and in the cumulative patient measures (ρ=0.781, P<0.0001). CONCLUSIONS: CP infusion did not alter recipient NAb titers. Pre-screening of CP may be necessary for selecting donors with high levels of neutralizing activity for infusion into patients with COVID-19.