The new 4CMenB vaccine may not protect against all invasive meningococcal B strains because the antigens included in the vaccine are expressed by only some of the strains in circulation. However, it is not known what protection 4CMenB vaccine provides against invasive meningococcal disease (IMD) because it depends on the vaccine antigens expressed by the meningococcal strains in any given geographical area and their cross-reactivity with the antigens included in the vaccine. Epidemiological and microbiological data regarding the circulating meningococcal strains are important in order to predict the theoretical coverage provided by 4CMenB vaccine and assess its impact on disease burden.