Meningococcal vaccines

The 5 major pathogenic serogroups of the Gram-negative encapsulated bacterium Neisseria meningitidis are A, B, C, Y, and W135. In the 1960s, vaccines consisting of purified capsular polysaccharide antigens were developed against serogroups A, C, Y, and W135. These vaccines were highly effective among adults but were not efficacious among infants and young children. Capsular polysaccharide-protein conjugate vaccines were subsequently developed.

The development of second-generation capsular polysaccharide glycoconjugate vaccines that are effective among infants and children is reviewed. The approaches for development of a broadly protective serogroup B vaccine, including attempts toward optimization of outer membrane vesicle vaccines and identification of conserved antigens, are discussed.

Monovalent serogroup C conjugate vaccines have been successful in reducing the burden of serogroup C meningococcal disease among infants, older children, and adults in the United Kingdom and Canada. Tetravalent serogroup A/C/W/Y conjugate vaccines are in late stage development. The use of serogroup B capsular polysaccharide as the basis for a vaccine for prevention of serogroup B meningococcal disease has proved problematic. The recent sequencing of the serogroup B genome led to the identification of additional, genome-derived, neisserial antigens, through a process called "reverse vaccinology."