In this study, we showed that a single treatment with NTHi lysate was sufficient to prevent otherwise fatal influenza pneumonia (Fig. 1) . The aerosolized lysate was also administered repetitively to model the sustained protection that would be clinically desirable during an influenza epidemic. No tachyphylaxis to the influenza-protective effect was observed with successive administrations (Fig. 2) , despite the fact that the rise in lung lavage neutrophils induced by the aerosolized lysate becomes less with repeated administration [26] . These findings are consistent with the development of tolerance to the inflammatory effects of innate immune stimulation without loss of antimicrobial effector function, as recently described [27] . Alternatively, the progressive reduction in inflammation could reflect the tempering of innate immune responses by adaptive immune cells that become engaged with repetitive stimulation [28] .