Meningococcal conjugate vaccine in adolescents and children.

Disease caused by Neisseria meningitidis is associated with high mortality rates and significant sequelae. Quadrivalent (A, C, Y, W-135) polysaccharide meningococcal vaccine has been available for more than 20 years, and although used widely for adolescents entering college, it has a number of limitations, including short duration of immunity and lack of a herd effect. A quadrivalent meningococcal conjugate vaccine has recently been licensed and endorsed for use in adolescents 11 to 12 years of age, at age 15, or at college entry. Among the key features of the new meningococcal conjugate vaccine are stimulation of both B-cell-dependent and T-cell-dependent immune responses, induction of immunologic memory and booster effects, long-term protection, reduction of nasopharyngeal carriage of N. meningitidis, and herd immunity. Large randomized, double-blind studies in adolescents and 2- to 10-year olds have demonstrated the immunogenicity as well as the safety and tolerability of the new meningococcal conjugate vaccine formulation.