Figure 4. Variant specific infection- or vaccine mediated humoral immunity.

Serology in IN or IM vaccinated and PI hamsters pre- and post-challenge with Delta/Omicron. Serum was collected 21 days post vaccination or infection with Delta, and on 5 DPI/DPE. A. Anti-spike IgG response, measured by ELISA. Whisker-plots depicting median, min and max values, and individuals. Kruskal-Wallis test, N = 16. B. Cross-reactivity of the IgG response, measured by Meso QuickPlex. Violin plots depicting median, quantiles, and individual values. Two-way ANOVA, followed by Šídák’s multiple comparisons test. N = 16. C. Individual neutralizing antibody titers against Delta and Omicron. Points connected by lines indicate the same animal. Two-way ANOVA, followed by Šídák’s multiple comparisons test. N = 16. D. Change in overall anti-spike IgG response after challenge (donors and sentinels). Whisker-plots depicting median, min and max values, and individual values. Change in titer is represented as Log₂ (fold change over pre-challenge value). Dotted line indicates no change in titer. Kruskal-Wallis test, N = 6. E. Change in cross-reactivity after challenge/re-infection in donors. Violin plots depicting median, quantiles, and individual values. Change in titer is represented as Log₂ (fold change over pre-challenge value). Dotted line indicates no change in titer. Two-way ANOVA, followed by Šídák’s multiple comparisons test. N = 16. F. Individual neutralizing antibody titers of donors against Delta and Omicron after challenge. Points connected by lines indicate the same animal. Two-way ANOVA, followed by Šídák’s multiple comparisons test. N = 6. black = naïve, dark blue = IM vaccinated, light blue = IN vaccinated, yellow = previously infected. P-values stated were significant (<0.05).