Antibody response to symptomatic infection with SARS-CoV-2 Omicron variant viruses, December 2021-June 2022.

To describe humoral immune responses to symptomatic SARS-CoV-2 infection, we assessed immunoglobulin G binding antibody levels using a commercial multiplex bead assay against SARS-CoV-2 ancestral spike protein receptor binding domain (RBD) and nucleocapsid protein (N). We measured binding antibody units per mL (BAU/mL) during acute illness within 5 days of illness onset and during convalescence in 105 ambulatory patients with laboratory-confirmed SARS-CoV-2 infection with Omicron variant viruses. Comparing acute- to convalescent phase antibody concentrations, geometric mean anti-N antibody concentrations increased 47-fold from 5.5 to 259 BAU/mL. Anti-RBD antibody concentrations increased 2.5-fold from 1258 to 3189 BAU/mL.
Competing Interests: Declarations: Dr. Zimmerman reports grants from CDC, during the conduct of the study, and grants from Sanofi Pasteur, outside the submitted work. Dr. Grijalva reports other from CDC, grants from NIH, other from FDA, grants and other from AHRQ, other from Merck, and other from Syneos Health, outside the submitted work. Dr. Talbot reports grants from CDC, during the conduct of the study. All other authors report not conflicts of interest.