Compared to T0, BA.5 infection induced strong recall responses in vaccinated individuals, leading to 1,315-fold, 1,020-fold, 587-fold, and 709-fold increased IgA titers specific to the ancestral, BA.5, XBB.1, and XBB.1.5 strains, respectively, at T1. The gene discussed is CD79A; the disease is infection.