CD79A and infection: We also assessed antibody responses to RBD proteins of endemic alpha and beta coronaviruses to compare variations in antibody kinetics throughout the course of infection.<h4>Results</h4>We found that increased serum IgA and mucosal secretory IgA antibody titers during the earliest phase of acute infection were associated with decreased viral shedding duration, with nasal IgA responses to the spike NTD being the strongest factor associated with viral shedding (adjusted p<0.1).