This study was hence aimed at assessing the humoral immune response developing after mRNA COVID-19 vaccination in a sample of baseline SARS-CoV-2 seronegative healthcare workers, with assessment of antibodies of both IgG and IgA classes, targeting the entire SARS-CoV-2 Spike protein trimer (anti-spike trimeric IgG), the RBD (anti-spike RBD IgG) or the S1 subunit (anti-spike S1 IgA), and thus reliably reflecting the neutralizing antibodies potential developing after vaccination. This evidence concerns the gene CD79A and COVID-19.