CD79A and infection: Several studies conclude that humoral mucosal immunity is largely driven by previous infection, with little impact of vaccination,4,5,6 while others suggest that mRNA vaccination can by itself elicit long-lasting anti–SARS-CoV-2 mucosal IgA responses.7,8,9,10,11 Herein, we compared individuals with previous SARS-CoV-2 infection and SARS-CoV-2–naive individuals included in the CoviCompare P and CoviCompare M vaccination trials12 for their saliva and serum responses after 2 different modes of antigenic challenge: infection and vaccination or vaccination alone.