Nontypeable Haemophilus influenzae (NTHI) utilize Type IV pili (Tfp) for adherence to airway epithelial cells, shown herein to be mediated via engagement with ICAM1. Adherence of Tfp-expressing NTHI was abrogated by pre-incubation of airway cells with recombinant PilA protein or by silencing ICAM1 gene expression. Upper respiratory tract viral infection induced greater expression of ICAM1 by airway cells and further augmented NTHI adherence; thus promoting continued development of Tfp-targeted vaccines for NTHI-induced diseases wherein respiratory tract viruses play a role.