Figure 4.

Antibody responses to variants of concerns elicited by vaccination or natural infection. (A–C) Anti-S1 IgG antibody avidity assessed using urea wash ELISA for alpha (A), beta (B), and delta (C) variants. Data are expressed as a ratio of urea-washed absorbance to unwashed absorbance for convalescent (black, n = 6), J&J (blue, n = 4), Moderna (orange, n = 7), and Pfizer (green, n = 7) participants. (D) Neutralizing antibody titers against delta variant are shown as log₁₀ of half-maximal inhibitory dilution (ID₅₀) for convalescent (black, n = 7), J&J (blue, n = 9), Moderna (orange, n = 8), and Pfizer (green, n = 8) participants. (D,E) Neutralizing antibody titers against omicron BA.1 variant are shown as log₁₀ of half-maximal inhibitory dilution (ID₅₀) for convalescent (black, n = 7), J&J (blue, n = 10), Moderna (orange, n = 8), and Pfizer (green, n = 9) participants. For all plots, * p < 0.05, and ** p < 0.01 by Kruskal–Wallis. Dotted line shows limit of detection of the assays. Median is shown by black horizontal bar and values above each group. (F) Summary plot of neutralization titers of delta and omicron BA.1 variants compared to ancestral WA.1 virus for each group. Box plots represent median (horizontal line within the box), and 25th and 75th percentiles (lower and upper border of the box) with individual results depicted with circles. Median are shown above each box plot. The fold change neutralization titers relative to WA-1 are depicted in text at the bottom of the panels.