Airway infection with Nontypeable Haemophilus influenzae is more rapidly eradicated in vitamin D deficient mice.

•Enhanced bacterial clearance in vitamin D deficient mice infected with NTHi.•Cigarette smoke inhibited phagocytosis and oxidative burst, but had no effect on bacterial clearance.•Faster resolution of local lung inflammation in vitamin D deficient mice.•Upregulation of CRAMP mRNA as possible mechanism for faster eradication in vitamin D deficient mice.•Misbalance of the protease and anti-protease homeostasis towards proteolysis in NTHi infected vitamin D deficient mice.