Neutralising SARS-CoV-2 RBD-specific antibodies persist at least 6 months independent of symptoms severity

 Angelika Wagner, Angela Guzek, Johanna Ruff, Joanna Jasinska, Ute Scheikl, Ines Zwazl, Michael Kundi, Hannes Stockinger, Maria R. Farcet, Thomas Kreil, Eva Hoeltl, Ursula Wiedermann

doi: https://doi.org/10.1101/2020.12.22.20248604

This article is a preprint and has not been certified by peer review [what does this mean?]. It reports new medical research that has yet to be evaluated and so should not be used to guide clinical practice.

PDF: https://www.medrxiv.org/content/10.1101/2020.12.22.20248604v1.full.pdf

Abstract

Background In spring 2020, at the beginning of the first pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wave in Europe, we set up an assay system for large-scale testing of virus-specific and protective antibodies including their longevity. Methods We analysed the sera of 1655 adult employees for SARS-CoV-2-specific antibodies using the S1 subunit of the spike protein of SARS-CoV-2. Sera containing S1-reactive antibodies were further evaluated for receptor-binding domain (RBD)- and nucleocapsid protein (NCP)-specific antibodies in relation to the neutralisation test (NT) results at 0, three and six months. Findings We found immunoglobulin G (IgG) and/or IgA antibodies reactive to the S1 protein in 10.15% (n=168) of the participants. In total, 0.97% (n=16) were positive for S1-IgG, 0.91% (n=15) were S1-IgG- borderline and 8.28% (n=137) exhibited only S1-IgA antibodies. Next, we evaluated the 168 S1-reactive sera for RBD- and NCP specificity: 8.33% (n=14) had detectable RBD-specific and 6.55% (n=11) NCP-specific antibodies. The latter correlated with NTs (kappa coefficient = 0.8660) but started to decline already after 3 months. RBD-specific antibodies correlated best with the NT (kappa = 0.9448) and only these antibodies were stable for up to six months. All participants with virus-neutralising antibodies reported symptoms, of which, anosmia and/or dysgeusia correlated best with the detection of virus-neutralising antibodies. Interpretation RBD-specific antibodies were most reliably detected post infection, independent of the number/severity of symptoms, and correlated best with protective neutralising antibodies at least for six months. They thus qualify best for large-scale seroepidemiological evaluation of both seroprevalence and seroprotection.

Competing Interest Statement

The authors A.W. A.G., J.R., J.J., I.Z., U.S., E.H., M.K., H.S. and U.W. declare no competing interest within the scope of this manuscript. M.R.F. and T.R.K. are employees of Baxter AG, now part of the Takeda group of companies, Vienna, Austria and have Takeda stock interest.

Clinical Trial

The study evaluated sera and demographic data and was therefore not registered for a trial ID.

Funding Statement

This study received funding from the Austrian Ministry of Education, Science and Research within the research framework in relation to the coronavirus disease 2019 pandemic (GZ 2020 0225 104).

https://www.medrxiv.org/content/10.1101/2020.12.22.20248604v1