Synergistic impact of N-antigenemia profiled by a rapid antigen test and low anti-S1 antibodies on the risk of hospitalization in COVID-19

Objectives: Identifying patients with COVID-19 who are at risk of poor evolution is key to early decide on their hospitalization. We evaluated the combined impact of nucleocapsid (N)-antigenemia profiled by a rapid test and antibodies against the S1 subunit of the SARS-CoV S protein (S1) on the hospitalization risk of patients with COVID-19. Methods: N-antigenemia and anti -S1 antibodies were profiled at admission to the emergency department in 146 patients with COVID-19 using the Panbio (R) antigen Rapid Test and the SARS-CoV-2 immunoglobulin G II Quant/SARS-CoV-2 immunoglobulin G assay from Abbott. A multivariable analysis was used to evaluate the impact of these factors on hospitalization. Results: Patients with a positive N -antigen test in plasma and anti -S1 levels < 2821 arbitrary units/mL needed hospitalization more frequently (20 of 23, 87%). A total of 20 of 71 (28.2%) of those showing a negative N -antigen test and anti -S1 >= 2821 arbitrary units/mL were hospitalized for 18 of 52 (34.6%) of the patients with only one of these conditions. Patients with a positive N -antigen test and low antibody levels showed an odds ratio, 95% confidence interval, and P -value for hospitalization of 18.21, 2.74-121.18, and 0.003, respectively, and exhibited the highest mortality (30.4%). Conclusions: Simultaneous profiling of a rapid N -antigen test in plasma and anti -S1 levels could help to early identify patients with COVID-19 needing hospitalization. (c) 2024 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY -NC -ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )