Neisseria meningitidis (N. meningitidis)

N. meningitidis is the leading cause of bacterial meningococcal disease.22 Five serogroups of N. meningitidis (A, B, C, W, and Y) are responsible for most infections. One out of every 10 individuals is a “carrier”. Carriers harbor the bacteria in the nasopharynx, but are asymptomatic. N. meningitidis is transmitted by airborne droplets and direct contact with respiratory secretions and saliva. Symptoms typically develop within 3-7 days after exposure.

Clinical Features

Following exposure, N. meningitidis is disseminated by the vascular system. A common outcome is inflammation of the meningeal membranes of the brain and spinal cord, i.e., meningitis. “Hallmark” symptoms of meningitis include sudden onset of fever, headache, and stiff neck. Other symptoms include nausea, vomiting, photophobia and altered mental state. Meningococcal meningitis can be fatal in as little as a few hours.

Complications include bacteremia or septicemia. Bacteria enter the bloodstream, they multiply, damage the blood vessels, and cause bleeding into skin and other organs. Symptoms include fatigue, vomiting, chills, cold hands and feet, severe pain (muscles, joints, chest, or abdomen), rapid breathing, diarrhea, and in the later stages, a dark purple rash. Meningococcal septicemia can be fatal in as little as a few hours.


Meningococcal disease is vaccine-preventable. There are six vaccines that provide protection against the dominant serogroups of N. meningitidis bacteria in the United States. Meningococcal conjugate vaccine (Menactra®, Menveo® and MenHibrix®) and meningococcal polysaccharide vaccine (Menomune®) are effective against serogroups A, C, W, and Y. Meningococcal vaccines Bexsero® and Trumenba® are effective against serogroup B.

Medical Management

Meningococcal disease can be treated with antibacterial agents. Treatment must begin promptly. Depending on how serious the infection is other treatments such respiratory support, medications for low blood pressure, and wound care for parts of the body with damaged skin may also be necessary. Even with treatment, 10 to 15% of those infected with meningococcal disease will die and another 11 to 19% of the survivors will have long-term disabilities.