(A) Patients with high and robust SARS-CoV-2 responses were more likely male, hospitalized (left), and of older age (right). (B) Low and high responders to SARS-CoV-2 showed limited neutralization in hyperpermissive HekAT24 clonal cells. Permissiveness is indicated by +. (C) Only elite responders showed neutralization in HekAT24 cells. (D) Serum titration curves from an elite responder (blue) showed IgG and IgM levels greater than low (red) and high (green) responders and incredibly high neutralization titers (≥10,000) that decreased and stabilized at high levels (≥1280). (E) The elite donor demonstrated stable high Spike IgG, but the early decrease in viral neutralization was parallel to IgM decline before stabilization (at high titer). PCR, polymerase chain reaction; SARS-CoV-2, Severe Acute Respiratory Syndrome Coronavirus 2.