Six-month antibody response to SARS-CoV-2 in healthcare workers assessed by virus neutralization and commercial assays

Abstract

34 35 We conducted a prospective study in healthcare workers (n=296) of the University Hospital of 36 Lyon, France. Serum samples (n=296) collected six months after disease onset were tested using 37 three commercial assays: the Wantai Ab assay detecting total antibodies against the receptor 38 binding domain (RBD) of the S protein, the bioMerieux Vidas assay detecting IgG to the RBD and 39 the Abbott Architect assay detecting IgG to the N protein. The neutralising antibody (NAb) titre 40 was also determined for all samples with a virus neutralisation assay (VNA) using live virus. The 41 positivity rate was 100% with the Wantai assay, 84.8% with the bioMerieux assay and 55.4% with 42 the Abbott assay. Only 51% of HCWs were positive for the presence of NAb. Less than 10 % of 43 HCWs had a NAb titre greater than 80. At a neutralising titre of 80, the area under the curves [IC 44 95%] was 0.71 [0.62-0.81], 0.75 [0.65-0.85] and 0.95 [0.92-0.97] for Wantai, Abbott and Vidas 45 respectively. The data presented herein suggest that commercial assays detecting antibodies against 46 the N protein must not be used in long-term seroprevalence surveys while the Wantai assay could 47 be useful for this purpose. VNA should remain the gold standard to assess the protective antibody 48 response, but some commercial assays could be used as first-line screening of long-term presence of 49 NAb. 50 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted December 9, 2020. ; https://doi.org/10.1101/2020.12.08.20245811 doi: medRxiv preprint