In September 2015, England became the first country in the world to introduce the meningococcal serogroup B (MenB) vaccine for routine use in infants. The vaccine (4CMenB, Bexsero®) contains four immunological components: factor H-binding protein, Neisserial heparin-binding antigen, Neisserial adhesion protein, and an outer membrane vesicle that contains a Porin protein. Because the vaccine is composed of bacterial proteins, and not the surrounding polysaccharide coat, it doesn’t cover all strains of MenB (predicted strain coverage in England was estimated to be about 88 percent).
Babies were immunized with 4CMenB at 2 and 4 months of age. The authors then followed children for 10 months, finding that the vaccine was 83 percent effective when vaccinated children were compared with unvaccinated children. Further, the vaccine induced a 50 percent reduction in the incidence of MenB disease compared with a similar-aged cohort of children from the previous four years. (Parikh SR, Andrews NJ, Beebeejaun K, et al. Effectiveness and Impact of a Reduced Infant Schedule of 4CMenB Vaccine Against Group B Meningococcal Disease in England: A National Observational Cohort Study, Lancet. 2016 Oct. In press.)
Typically, meningococcal vaccines (both MenACWY and MenB) have been licensed based on safety and immunogenicity data. Because meningococcal disease is uncommon, licensing agencies haven’t required efficacy studies. As a consequence, few efficacy studies exist. The England experience provides excellent evidence for the effectiveness of 4CMenB vaccine against all laboratory-confirmed cases of MenB disease, irrespective of predicted strain coverage. Although duration of effectiveness has yet to be determined, these data are very encouraging.