Convalescent plasma from Norwegian blood donors to treat COVID-19.

Abstract

At the start of the pandemic, the Norwegian Directorate of Health and Norwegian blood banks initiated the production of COVID-19 convalescent plasma within the framework of clinical studies. In this article we describe the blood donors who participated. Blood donors who had recovered from COVID-19 were recruited to donate single donor plasma for the purpose of patient treatment. Data on the course of infection, leukocyte antibodies and antibody level against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) per plasma unit were registered after informed consent was obtained. We calculated a disease score defined as the total number of self-reported symptoms/findings and hospitalisation where relevant (score 0-⁠11). A total of 1644 plasma units were collected from 266 plasma donors at 12 blood banks. Median disease score was 5 (interquartile range 3-⁠6), and 15 donors had recovered from pneumonia and/or been hospitalised. A total of 599/1644 plasma units from 106/266 donors met our requirement for SARS-CoV-2 antibody content (>60% inhibition of virus binding to angiotensin-converting enzyme 2 (ACE2)) or positive virus neutralisation test. The antibody level in donors waned over time following infection, and showed no clear correlation with disease score. The number of symptoms and findings in blood donors could not predict antibody response at individual level, and antibody testing was crucial for the production of effective convalescent plasma.