Further, whereas mucosal IgA levels measured in stool samples have been previously shown to provide a robust indication of vaccine-induced protection in the context of polio (eg, see [31, 32]), the mucosal IgA levels measured in NPW specimens in this study exhibit a high degree of variance that limits their utility; further research is needed to optimize NPW sampling methods and refine the ascertainment of influenza-specific mucosal IgA. The gene discussed is CD79A; the disease is poliomyelitis.