Furthermore, several studies into COVID-19 have shown the presence of serum IgA against SARS-CoV-2 (70, 77–79) and, in preclinical studies with anti-SARS vaccines, administered either sub-lingually or intranasally, the presence of neutralizing IgA was demonstrated in bronchoalveolar lavages (80–82). This evidence concerns the gene CD79A and COVID-19.