A composition comprising (a) Neisseria meningitidis serogroup B outer membrane vesicles (OMVs), and (b) an immunogenic component selected from other Neisseria proteins, or immunogenic fragments thereof. Component (b) preferably includes a protein from a different NmB strain from that from which the OMV of component (a) is derived. The OMVs are preferably obtained by deoxycholate extraction. Optionally, the composition may also comprise a protective antigen against other pathogens.
