CD79A and hyperinsulinemic hypoglycemia, familial, 4: Lack of neutralizing anti-SARS-Cov-2 IgA and secretory IgA antibodies represents a possible cause of prolonged viral shedding in patients with Selective IgA Deficiency and in patients with Primary Antibody Deficiencies showing an increased length of SARS-CoV-2 positivity.