It is particularly well established that intranasal live attenuated influenza vaccines (LAIV) provide equivalent protection to inactivated vaccine although HI titers are invariably lower and underestimate efficacy.7,29,31–35 Neutralizing antibody titer, influenza specific airway IgA, influenza specific IgG + B cell frequency, or combinations of these factors correlate better with LAIV efficacy.33–36 Nevertheless, a number of natural infection cohorts have demonstrated correlations between homologous HI titers and protection against H1N1 infection. This evidence concerns the gene CD79A and influenza.