Three antigens (Neisserial adhesin A (NadA) allele 3, Neisseria Heparin Binding Antigen (NHBA), factor H-binding protein (fHbp) variant 1 along with OMV of the epidemic strain (PorA P1.4) from New Zealand have been combined into a recently approved vaccine against MenB disease (4CMenB) [8] and [9].

Two variants of fHbp have also been used to create an investigational bivalent MenB vaccine (rLP2086) [10]. To date, three OMV-based vaccines against invasive MenB disease have successfully contained clonal outbreaks in various countries [11], [12] and [13]. However, immunogenicity of these vaccines was primarily based on the PorA outer membrane protein contained in the OMV and did not provide protection against strains carrying different PorA subtypes [14]. Antigens included in the newer MenB vaccines have MLN0128 concentration the potential find more to provide broad cross-protection against MenB strains and potentially other serogroups. The predicted protection afforded by these newer vaccines is not known and will be highly dependent on both the quantity of vaccine antigens expressed by strains causing

disease in a given geographic area and on the extent of their immunologic cross reactivity with the corresponding antigen in the vaccine. To this end, the Meningococcal Antigen Typing System (MATS) was developed to predict which individual MenB strains are likely to be covered by the 4CMenB vaccine [15]. To understand the potential coverage, a detailed epidemiologic, because microbiologic and genetic characterization of the antigens found in MenB disease isolates is required. In collaboration with the Canadian Immunization Monitoring Program Active (IMPACT) surveillance network, the National Microbiology Laboratory (NML), the UK Health Protection Agency (HPA) and Novartis Vaccines & Diagnostics, we tested the potential strain coverage of the 4CMenB vaccine against invasive MenB strains isolated in Canada from 2006 to 2009. During this

time the incidence rate of MenB infection was stable at 0.25 per 100,000, but a higher rate occurred in Québec as a result of the circulation of clonal complex (cc) 269, [2], [16] and [17] one of two hyper-endemic ccs in Canada. Active, metropolitan area population-based surveillance for adult and pediatric hospital admissions related to infection with Neisseria meningitidis was conducted by the 12 centers of the IMPACT, in collaboration with local public health officials. IMPACT is a national surveillance initiative with centers located in 8 provinces [18]. Each center defined a population area and captured all IMD cases in children and adults. IMPACT meningococcal surveillance includes over 17 million Canadians, just over 50% of the population. Inclusion as a case required the isolation of N.