meningococcal polysaccharide a

Meningococcal polysaccharide A is a purified polysaccharide antigen derived from the capsule of *Neisseria meningitidis* serogroup A. It is used as the antigenic component in monovalent and polyvalent polysaccharide vaccines to prevent invasive meningococcal disease, especially meningitis. The vaccine acts by inducing antibodies against the serogroup A capsule, thereby providing direct protection against infection. It does **not** induce immunological memory nor reduce bacterial carriage, because as a T-cell independent antigen it typically does not stimulate long-lasting immunity or herd protection. Meningococcal polysaccharide vaccines have historically been used in epidemic response and routine immunization programs in regions with high disease burden, particularly in sub-Saharan Africa. They have largely been supplanted by conjugate vaccine formulations, which offer more robust and lasting immunity, including in infants. The mechanism of action is the induction of an antibody response that targets the polysaccharide capsule of serogroup A *Neisseria meningitidis*, neutralizing the bacteria and preventing invasive disease.[1][2]

Other names

serogroup A meningococcal polysaccharidemeningococcal A polysaccharide