The present invention provides immunogens which can be used for vaccines against non-typeable Haemophilus influenzae (NTHi). The protein targeted is NTHi PDE1 and is highly conserved making it a vital component necessary for bacterial pathogenesis. The protein preferably includes the C terminal fragment after cleavage between Asn269 and Gly270, when compared to the wild-type PDE1 amino acid sequence. Nucleic acid sequences, amino acid sequences, immunogenic compositions, treatments and methods of diagnosis are disclosed.
