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Temporal Analysis of Serial Donations Reveals Decrease in Neutralizing Capacity and Justifies Revised Qualifying Criteria for COVID-19 Convalescent Plasma

The Wadsworth Center, New York State Department of Health, Albany, New York, USA. New York Blood Center Enterprises, New York, NY, USA. The Department of Biomedical Sciences, The School of Public Health, The University at Albany, Albany, New York, USA.

The Journal of infectious diseases. 2021
Abstract
BACKGROUND COVID-19 convalescent plasma (CCP) received an Emergency Use Authorization by the FDA. CCP with a signal-to-cutoff ratio of ≥12 using the Ortho VITROS SARS-CoV-2 IgG test (OVSARS2IgG) is permitted to be labeled "high titer". Little is known about the relationship between OVSARS2IgG ratio and neutralizing capacity of plasma/sera against genuine SARS-CoV-2 virus. METHODS 981 samples from 196 repeat CCP donors 0-119 days post initial donation (DPID) were analyzed. Neutralizing capacity was assessed for 50% (PRNT50) and 90% (PRNT90) reduction of infectious virus using the gold standard plaque reduction neutralization test (PRNT). A subset of 91 donations were evaluated by OVSARS2IgG and compared to PRNT titers for diagnostic accuracy. RESULTS 32.7%/79.5% (PRNT90/PRNT50) of donations met a 1:80 titer initially but only 14.0%/48.8% (PRNT90/PRNT50) met this cut-off ≥85 DPID. Correlation of OVSARS2IgG results to neutralizing capacity allowed extrapolation to CCP therapy results. CCP with OVSARS2IgG ratios equivalent to a therapeutically beneficial group had neutralizing titers of ≥1:640 (PRNT50) and/or ≥1:80 (PRNT90). Specificity and positive predictive value of the OVSARS2IgG for qualifying highly neutralizing CCP was optimal using ratios significantly greater than the FDA cut-off. CONCLUSIONS This information provides a basis for refining the recommended properties of CCP used to treat COVID-19.
Study details
Language : eng
Credits : Bibliographic data from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine