key: cord-0736820-tprr7cec
authors: Levring, Mette B.; Holm, Dorte K.; Nilsson, Anna C.; Bauer, Joschka M.; Jensen, Iben S.; Davidsen, Jesper R.; Rasmussen, Line D.; Sprogøe, Ulrik; Lillevang, Søren T.
title: SARS‐CoV‐2 antibody kinetics in blood donors with a previously positive SARS‐CoV‐2 antibody test within a seroprevalence survey
date: 2021-12-08
journal: J Med Virol
DOI: 10.1002/jmv.27486
sha: a5bc075457578f6dab59c6cb0972d07744cec63c
doc_id: 736820
cord_uid: tprr7cec

The persistence of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) antibodies is a matter of importance regarding the coronavirus disease 19 (COVID‐19) pandemic. To observe antibody dynamics, 105 blood donors, positive for SARS‐CoV‐2 antibodies by a lateral flow test within a seroprevalence study, were included in this study. Thirty‐nine (37%) of 105 the donors were confirmed positive by a total Ig Wantai enzyme‐linked immunosorbent assay (ELISA). Three (8%) in this group of 39 reported severe and 26/39 (67%) mild to moderate COVID‐19 symptoms. By further ELISA‐testing, 33/39 (85%) donors were initially positive for IgG antibodies, 31/39 (79%) for IgA, and 32/39 (82%) for IgM, while 27/39 (69%) were positive for all three isotypes. Persistence of IgG, IgA, and IgM was observed in 73%, 79%, and 32% of donors, respectively, after 6–9 months of observation. For IgM antibodies, the decline in the proportion of positive donors was statistically significant (p = 0.002) during 12 months observation, for IgG only the decline at 3 months was statistically significant (p = 0.042). Four donors exhibited notable increases in antibody levels. In conclusion, persistent SARS‐CoV‐2 IgA antibodies and IgG antibodies at 6–9 months are present in approximately three of four individuals with previous mild to moderate COVID‐19.

risk for reinfection. 8 The aim of this prospective observational study was to investigate the dynamics of binding antibody levels over time and to observe reinfections after mild to moderate COVID-19 in a cohort of Danish blood donors. 

A blood sample was collected from each donor at inclusion and at each subsequent donation. All samples were tested/re-tested for SARS-CoV-2 antibodies using four semi-quantitative CE-IVD ap- Common symptoms were fatigue (62%), dry cough (62%), fever (20%), and a sore throat (20%). Three of 66 (5%) were aware of SARS-CoV-2 exposure and none had been hospitalized.

Detection of SARS-CoV-2 Total Ig antibodies was associated with the presence of fever (p < 0.001), dry cough (p < 0.01), shivers (p = 0.02), fatigue (p < 0.001), reduced sense of smell (p < 0.001), or reduced sense of taste (p < 0.001) (χ 2 test). There was no correlation between symptom severity and IgG (p = 0.63) or IgA (p = 0.79) antibodies (χ 2 test). In conclusion, this study shows that persistent SARS-CoV-2 IgA antibodies and IgG antibodies at 6-9 months are present in approximately three of four individuals with previous mild to moderate .

We thank the Department of Clinical Immunology for finances and staff making this study possible. We thank the volunteer blood donors participating. The Open Patient Exploratory 

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Assessment of protection against reinfection with SARS-CoV-2 among 4 million PCR-tested individuals in Denmark in 2020: a population-level observational study

A systematic review on the recurrence of SARS-CoV-2 virus: frequency, risk factors, and possible explanations

Evaluation of six commercial mid-to high-volume antibody and six point-of-care lateral flow assays for detection of SARS-CoV-2 antibodies

T-cell responses and therapies against SARS-CoV-2 infection

SARS-CoV-2 antibody kinetics in blood donors with a previously positive SARS-CoV-2 antibody test within a seroprevalence survey

The authors declare that there are no conflict of interests. 

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

https://orcid.org/0000-0002-4366-382X