To validate that IgG and/or IgA antibody responses against the P particles are elicited by norovirus infection, we tested four pre- and post-infection sera of immunocompetent adults who had a norovirus infection with a known capsid genotype: either GI.1, GII.3, or GII.4 (New Orleans 2009 and Den Haag 2006b). This evidence concerns the gene CD79A and infection.