Neisseria meningitidis or meningococcus (serogroups A, B, C, Y, and W-135) is a leading cause of bacterial meningitis. The infection is highly contagious and is spread by airborne droplets and contact with respiratory secretions. Meningococcal meningitis occurs when N. meningitidis from an upper respiratory tract infection enters the bloodstream and causes inflammation of the meninges surrounding the brain and spinal cord. "Hallmark" signs and symptoms include headache, fever and a stiff neck.11,29
Three quadrivalent vaccines are available against N. meningitidis serogroups A, C, Y, and W0135 (Table 7). Menomune contains meningococcal unconjugated capsular polysaccharides. Menactra and Menveo contain capsular polysaccharides conjugated to different diphtheria toxoid proteins. All adults should receive a single dose of conjugated (if <55 years old) or unconjugated (if ≥55 years old) vaccine. Adults with a compromised immune system should receive two doses of conjugated vaccine (if <55 years old) or one dose of unconjugated vaccine (if ≥55 years old).