Fig. 2.

Kinetics analysis of IgE response, showing that the index is higher in subjects previously diagnosed with COVID-19 and rises after each vaccine dose, especially after the booster, regardless of group: (A) ChAd (n = 9), (B) ChAd-cov (n = 9), (C) Corona (n = 22), or (D) Corona-cov (n = 19). The ELISA index refers to the ratio between the optical density (OD) of the sample and thecutoff value. The dotted line shows the cutoff of anti-RBD IgE. The responses at each dose were compared using the Friedman test followed by Dunn’s post hoc test.