Neisseria meningitidis (meningococcus) is a bacterium which causes meningitis and septicaemia. There are 13 serogroups of meningococcus, 6 (A, B, C, W, X and Y) cause most disease of which MenB is the most common cause of meningococcal disease in the UK. Infants have the highest incidence of MenB disease in the UK and across Europe, with the main burden of disease falling in the second 6 months of life.
In 2015 the UK became the first country in the world to introduce Men B vaccination with 4CMenB (Bexsero®) into its routine schedule, with a two-dose priming regime at 2 and 4 months with a booster at 12 months. The vaccine has proved to be very effective in preventing invasive MenB disease in immunised infants (Parikh et al, 2016). This study also showed that a single dose of 4CMenB however, was not effective. Half the MenB cases diagnosed after 16 weeks of age in the vaccine-eligible infant cohort were either unvaccinated or partially vaccinated (i.e. received only a single dose of 4CMenB). Such cases could potentially have been prevented through timely or, preferably, earlier completion of the primary immunisation schedule.