Last updated 17 April 2022
Symptoms and Causative Agent
Neisseria meningitidis bacteria, also called meningococcus [meningococci (plural)], are an important cause of bacterial meningitis and sepsis (bloodstream infection) in the United States. Meningococci can also cause pneumonia, otitis media (ear infection), arthritis, and other infections, although these are less common. Collectively, the different illnesses caused by N. meningitidis are referred to as meningococcal disease.
Meningococcal meningitis symptoms include fever, headache, confusion and stiff neck, which may also be accompanied by nausea, vomiting, and sensitivity to light. Meningococcal bacteremia (or meningococcemia – bloodstream infection) symptoms include sudden fever onset and rash. Other forms of meningococcal disease have symptoms related to the organ affected: otitis media has ear pain; arthritis has joint pain and swelling.
Invasive meningococcal disease can be fatal; survivors may have permanent injury, including brain damage, hearing loss, or loss of a limb.
As many as 10-20% of adolescents and adults are colonized by N. meningitidis without becoming ill. These individuals may carry the bacteria for weeks or months. The bacteria can be spread to others via direct contact, such as kissing, or respiratory secretions due to coughing or sneezing.
Individuals with abnormal spleen function are at an increased risk for severe meningococcal disease. HIV infection and some genetic factors are also likely to increase the risk of meningococcal disease, as is cigarette smoking. Family members of an infected person also have an increased risk.
Although meningococcal epidemics do not occur on a national level in developed countries, there is a risk to travelers who visit parts of the world where epidemics occur regularly. The highest risk region for epidemic meningococcal disease is sub-Saharan Africa.
Treatment and Care
Antibiotics are used to treat meningococcal disease. Because the symptoms of meningococcal meningitis are similar to forms of meningitis caused by other bacteria, the antibiotics initially used in treatment may provide broad coverage until it can be confirmed that N. meningitidis is the cause of the infection. After this has been confirmed, penicillin or another appropriate single agent can be administered to complete the course of treatment.
Complications and Mortality
Invasive meningococcal disease can be extremely serious. Meningococcal meningitis, the most common presentation of meningococcal disease, “should always be viewed as a medical emergency” and requires admission to a hospital, according to the World Health Organization.
In the United States, between 1,400 and 2,800 cases of meningococcal disease occur each year. Invasive meningococcal disease can be fatal: even with antibiotic treatment, the case fatality rate is between 9-12%. Up to 20% of survivors of invasive meningococcal disease have permanent injury, including brain damage, hearing loss, or loss of a limb.
Available Vaccines and Vaccination Campaigns
Five serogroups—groups of bacteria that contain a common antigen that can generate an immune response—are collectively responsible for nearly all invasive meningococcal disease: groups A, B, C, Y, and W-135. Four of these (all but serogroup B) are covered by quadrivalent meningococcal vaccines used in the United States.
There are two main types of meningococcal vaccines. A meningococcal polysaccharide vaccine has been available since the 1970s. However, like the polysaccharide vaccine against pneumococcal disease, it is most effective in adults and does not consistently generate immunity in young children.
The first conjugate meningococcal vaccine in the United States, MCV4 (Menactra), was licensed in 2005, with a second, MenACWY-CRM (Menveo), licensed in 2010. These are the preferred vaccines for individuals between two years and 55 years of age; Menactra is approved for ages two to 55, and Menveo for ages 11 to 55. (See our article, , for more on how these vaccines are made.)
Vaccines for group B meningococcal disease were licensed in the United States in 2014 and 2015. MenB-FHbp (Trumenba, Wyeth Pharmaceuticals, Inc.} is a three-dose vaccine, and MenB-4C (Bexsero, Novartis Vaccines) is a two-dose vaccine.
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