Several studies have demonstrated that mucosal IgA exhibit a broader virus neutralizing capacity than serum IgG, not only blocking the virus at the site of entry and thereby reducing the risk of infection but also decreasing onward transmission.14, 15, 16, 17 However, although systemic administration of vaccines against respiratory pathogens induces IgG antibodies in serum which may reach the respiratory mucosa via transudation and FcRn-mediated transport, systemic vaccines fail to induce mucosal IgA responses.10 This evidence concerns the gene CD79A and infection.