Flumist is an intranasal influenza vaccine approved by the FDA in persons 2–49 years of age [17], intranasal administration of Bacillus Calmette–Guérin (BCG) shows promising results in the prevention of MTB infection [18], and BPZE1, an intranasal live attenuated pertussis vaccine, consistently induced a broad pertussis-specific mucosal secretory IgA responses, whereas the conventional injectable Tdap did not [19,20]. This evidence concerns the gene CD79A and pertussis.