This randomised, open-label, single-centre, descriptive study aims to investigate gene expression (i.e what genes are 'switched on' and 'off') following vaccination with 4CMenB and to relate this to vaccine reactions and to immune response. 160 healthy Caucasian infants aged 8-12 weeks (at time of first visit) who have not yet received their routine infant immunisations will be recruited. Participation in the study will be limited to to Caucasian infants (defined as having two Caucasian parents). This is so that baseline variability in gene expression data which is to some degree affected by ethnicity is reduced. Participants will be randomised to either a 'test' group or 'control' group depending on what 4CMenB schedule they receive, with 80 infants in each. All participants will receive the usual paediatric immunisations according to the UK national immunisation schedule. In addition, participants in the test groups will receive 4CMenB at 2, 4 and at 12 months while those in the control groups will receive the same vaccine at 5, 7 and 13 months. Blood samples will be taken from each infant at specified time points before and after vaccination to address the objectives of the study. In addition, oro-pharyneal swabs will be obtained around different vaccination timepoints to investigate the effect of 4CMenB vaccination on the oro-pharyngeal Neisseria microbiome.

The incidence of meningococcal disease is 0.2-14 per 100,000 in industrialized countries. In England and Wales, during the period 2005-2010, there were 900-1300 cases annually. Disease is commonest in infants, young children and adolescents and case fatality is high at 8-10%. Until recently there were no licensed vaccines against serogroup B meningococcal disease, although vaccines against epidemic strains of MenB have been used in several countries. Unfortunately, 4CMenB is associated with significant reactogenicity. This is presumably related to the presence of various bacterial surface components present in the outer membrane vessicles (OMVs), including lipopolysacchride (LPS), which are capable of activating the innate immune response. The host pathways responsible for reactogenicity to OMV vaccines, and indeed to other vaccines, are not yet established, and the relationship between reactogenicity and immunogenicity is not clear. This study will provide information about pathways and mechanisms of immunity and may identify gene expression signals which can be used in future vaccine design and evaluation.