Serum anti-RBD IgA levels at 2 months were 2.82 (SEM, 0.128) log10(AU/mL) and 1.74 (SEM, 0.0516) log10(AU/mL) in the previously infected and infection-naive groups, respectively (P < 0.0001) (Fig. 3b). Here, CD79A is linked to infection.