Figure 4.

A, Comparison of serum or plasma nucleocapsid levels in individuals with and without SARS-CoV-2–specific antibodies. Samples were tested by in-house developed serological tests for nucleocapsid- and receptor binding domain-specific IgG as well as receptor binding domain-specific IgA and IgM. Levels of nucleocapsid are plotted and compared in samples stratified by seropositivity for each antibody type. B, Comparison of nucleocapsid levels by serostatus pattern. RBD positive/N negative is most consistent with prior vaccination. RBD positive /N positive is most consistent with natural infection with or without prior vaccination. Abbreviations: Ig, immunoglobulin; N, nucleocapsid; RBD, receptor-binding domain; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.