Figure 1.

Association between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody responses and coronavirus disease 2019 mortality rate. A, Spike receptor binding domain and nucleocapsid immunoglobulin G levels for each participant were measured longitudinally, using optical density (OD) readout of enzyme-linked immunosorbent assays for a standard serum dilution. Neutralization activity was determined using a live SARS-CoV-2–mNeonGreen (mNG) reporter assay, reported as the serum titer preventing 50% of infection (NT₅₀). Dotted line represents designated seropositivity threshold for each assay. B, Kaplan-Meier survival curves for patients with initial NT₅₀ values >80 or <80 (P = .003; Mantel-Cox test). C, Dot plots comparing NT₅₀ values on day 1 among participants grouped by 29-day survival outcome. Dotted line represents limit of detection (LoD; 1:20) of neutralization assay. Statistical analysis was conducted with Mann-Whitney U test; P = .01