Meningococcal disease is a bacterial disease caused by the gram-negative aerobic bacterium Neisseria meningitidis (N. meningitidis).⁽¹⁾ Thirteen serogroups of N. meningitis or meningococci were identified⁽²⁾ and six were found responsible for invasive meningococcal disease. These six serogroups include A, B, C, X, W and Y.⁽³⁾ More commonly, invasive meningococcal disease can cause inflammation of the meninges of the brain and spinal cord (meningitis) and a serious infection of the bloodstream (septicaemia/meningococcemia).⁽⁴⁾

Symptoms of meningococcal meningitis include headache, stiff neck, and fever, while symptoms of meningococcemia include rash and fever. Meningitis is the most common presentation of invasive meningococcal disease, accounting for approximately 75% of all cases. 20% of cases of invasive meningococcal disease result in meningococcemia. Both meningitis and meningococcemia can be fatal, with 10-15% of cases resulting in death.⁽⁵⁾

Symptoms of meningitis begin to appear between 3 and 7 days after exposure to the meningococcal bacterium. At first, symptoms may seem mild and similar to a cold or flu and may include headache, fever, aches and pains. As the disease progresses, other symptoms may include rash, severe headache, stiff neck, nausea, vomiting, inability to look at bright lights, mental confusion and irritability, extreme tiredness/drowsiness, seizures, and loss of consciousness. In babies, symptoms may include a high-pitched, whiny cry, difficulty or refusal to feed, and the fontanel, the soft area on the top of the head, may also be swollen.^(6-7)

About 10-20% of adolescents and adults are asymptomatic carriers of meningococci. Although they have no symptoms of the disease, they carry the bacteria in the back of their throats and can transmit the disease to others.⁽⁸⁾ Less than one percent of people with meningococci will develop invasive meningococcal disease. Invasive disease occurs when the meningococcal bacterium crosses mucous cells and invades the bloodstream. Invasive meningococcal disease has often been found after the development of an upper respiratory infection.⁽⁹⁾

Meningococcal disease doesn't spread easily, and transmission requires that you are susceptible to the disease and have prolonged, direct contact, such as kissing or sharing a toothbrush, with a person colonizing the bacteria.^(10-11) Studies have also found that genetics play a role in both susceptibility to invasive meningococcal disease and disease outcomes.⁽¹³⁾ Meningococcal disease is treated with antibiotics, and cephalosporins are currently considered the antibiotic of choice for treatment.⁽¹³⁾ People who may have been exposed to meningococcal bacteria through close contact with a person diagnosed with invasive disease may be treated with antibiotics such as rifampin or ciprofloxacin prophylactically to prevent the disease from developing.⁽¹⁴⁾