Severe Acute Respiratory Syndrome Coronavirus 2 Neutralizing Antibody Titers in Convalescent Plasma and Recipients in New Mexico: An Open Treatment Study in Patients With Coronavirus Disease 2019

J Infect Dis. 2020 Oct 13;222(10):1620-1628. doi: 10.1093/infdis/jiaa505.


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 patients with acute COVID-19 remains largely undetermined. We measured NAb titers in CP and in patients with acute COVID-19 before and after transfusion through the traditional Food and Drug Administration investigational new drug 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 2 infection.

Results: NAb titers in the donor CP units were low (<1:40 to 1:160) and had no effect on recipient neutralizing activity 1 day after transfusion. NAb titers were detected in 6 of 12 patients on enrollment and in 11 of 12 at ≥2 time points. Average titers peaked on day 7 and declined toward day 14 (P = .004). Nab titers and immunoglobulin G levels were correlated in donor plasma units (ρ = 0.938; P < .001) and in the cumulative patient measures (ρ = 0.781; P < .001).

Conclusions: CP infusion did not alter recipient NAb titers. Prescreening of CP may be necessary for selecting donors with high titers of neutralizing activity for infusion into patients with COVID-19.

Clinical trials registration: NCT04434131.

Keywords: SARS-CoV-2; antibodies; convalescent; coronavirus; neutralizing; plasma.

Publication types

  • Clinical Trial

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antibodies, Neutralizing / blood*
  • Antibodies, Viral / blood*
  • Betacoronavirus / genetics
  • Betacoronavirus / immunology*
  • Blood Donors*
  • COVID-19
  • COVID-19 Serotherapy
  • Cohort Studies
  • Coronavirus Infections / epidemiology*
  • Coronavirus Infections / therapy*
  • Coronavirus Infections / virology
  • Female
  • Humans
  • Immunization, Passive
  • Immunoglobulin G / blood
  • Male
  • Middle Aged
  • New Mexico / epidemiology
  • Pandemics
  • Pneumonia, Viral / epidemiology*
  • Pneumonia, Viral / therapy*
  • Pneumonia, Viral / virology
  • RNA, Viral / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • SARS-CoV-2
  • Spike Glycoprotein, Coronavirus / immunology
  • Treatment Outcome


  • Antibodies, Neutralizing
  • Antibodies, Viral
  • Immunoglobulin G
  • RNA, Viral
  • Spike Glycoprotein, Coronavirus
  • spike protein, SARS-CoV-2

Associated data