Meningococcal Vaccines Directed at Capsular Group B

Neisseria meningitidis group B (MenB) remains a global cause of meningitis and sepsis-especially in infants, young children, and adolescents, and of acute and prolonged meningococcal outbreaks. The protein antigens used in the MenB vaccines are novel and have distinct immunogenic properties different from those associated with the capsular polysaccharide-based vaccines. Two vaccines directed at MenB are in widespread use. MenB-FHbp contains two recombinant Factor H binding protein (FHbp) lipoprotein molecules, one from each major subfamily. MenB-4C contains a subfamily B FHbp sequence variant and three additional components- Neisseria Adhesin A (NadA), Neisseria Heparin binding antigen (NHba), and outer membrane vesicles (OMVs) containing as a dominant antigen the porin protein (PorA) serosubtype P1.4. Both vaccines elicit human serum bactericidal activity (SBA) against many but not all (and sometimes different) group B strains and against some non-group B strains. Vaccine effectiveness of ≥75% has been seen in infants and in the control of outbreaks. MenB-4C or MenB-FHbp are associated with higher rates of local and systemic reactions than with other commonly administered vaccines but prelicensure and post licensure studies have not detected an excess of serious adverse events related to either vaccine. Unlike the meningococcal polysaccharide-protein conjugate vaccines the MenB vaccines have shown no significant effect on meningococcal carriage. For individuals that remain at high risk, boosters should be administered at 1 year after primary series completion, then every 2-3 years thereafter. Next generation MenB vaccines in development combine the MenB protein antigens with the quadrivalent polysaccharide-protein conjugate vaccines.