Neisseria meningitidis serogroups A, C, Y, and W-135 (MenACWY)

Neisseria meningitidis serogroups A, C, Y, and W-135 refers collectively to specific serogroups (capsular types) of the bacterium *Neisseria meningitidis*. These serogroups are defined by the distinct antigenic composition and structure of their polysaccharide capsules, which serve as major virulence factors enabling the bacterium to evade host immune responses and cause invasive disease, including meningitis and meningococcemia. The capsular polysaccharides of serogroups A, C, Y, and W-135 represent four distinct chemical entities that are key determinants in pathogenicity. Vaccines targeting these antigens are formulated by conjugating purified capsular polysaccharides to protein carriers, such as diphtheria toxoid or CRM197, to enhance immunogenicity and induce robust, long-lasting antibody responses. These quadrivalent meningococcal conjugate vaccines are essential components of public health strategies for the prevention of meningococcal disease globally, especially in populations at risk for epidemic outbreaks (e.g., African meningitis belt) and among travelers, infants, adolescents, and military recruits. Diagnostic PCR panels target serogroup-specific capsule synthesis genes for rapid molecular identification. It is important to note that while serogroups B and X also cause invasive disease, they are not covered by vaccines targeting A, C, Y, and W-135.

Other names

Meningococcal serogroups A, C, Y, and W-135MenACWYquadrivalent meningococcal capsular polysaccharidesmeningococcal group A/C/Y/W-135tetravalent meningococcal capsular polysaccharide antigens

For vaccines: induction of protective anti-capsular polysaccharide antibodies (primarily IgG) via conjugation of polysaccharide antigens to a protein carrier, leading to complement-mediated bacterial killing.