CD79A and COVID-19: As concerns the specific post-vaccination kinetics of serum neutralizing IgA antibodies compared to that of IgG, our data showed that Pfizer COVID-19 mRNA vaccine administration elicited a very sustained response of anti-spike trimeric IgG (576-fold from baseline) and anti-spike RBD IgG (1426-fold from baseline), whilst the increase of anti-spike S1 IgA was apparently weaker (around 20-fold from baseline), yet detectable and likely of clinical significance.