CD79A and infection: Homologous primary vaccination with ChAdOx1 not only showed less potent NTAb, TAb, anti‐S‐RBD IgG, and anti‐S1 IgA immune responses compared to primary BNT162b2 or mRNA‐1273 vaccination regimens (p < 0.05) but also showed ~3‐fold less anti‐S1 IgA response compared to infection‐induced immunity (p < 0.001).