Meningococcal meningitis can kill up to 50 percent of people infected if left untreated.
It is a bacterial form of meningitis, a serious infection of the thin lining that surrounds the brain and spinal cord.
Meningococcal meningitis occurs throughout the world but the vast majority of infections and deaths are in Africa, particularly across the "meningitis belt", stretching from Senegal in the west to Ethiopia in the east.
According to the World Health Organization (WHO), there were over 900,000 cases in the area in the last 20 years (1995-2014). Around 30,000 cases are still reported each year.
The infection can progress rapidly, and death can follow within hours of the onset of symptoms.
However, even when the disease is diagnosed early and adequate treatment is started, up to 10 percent of patients do not survive. Left untreated, up to 50 percent of cases may die.
Among survivors, 10 to 20 percent are left with lifelong conditions such as deafness, mental retardation and epilepsy.
Vaccines are used for prevention and in response to outbreaks.
In 2019, MSF treated 4,970 people for meningitis.
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Meningitis: Key facts
FATALITY RATE IF LEFT UNTREATED
PEOPLE TREATED FOR MENINGITIS BY MSF IN 2019
CASES REPORTED ACROSS THE MENINGITIS BELT EACH YEAR
Guide to meningitis
Six strains of the bacterium Neisseria meningitidis are known to cause meningitis. People can be carriers without showing symptoms and transmit the bacteria when they cough or sneeze.
Overcrowding and cramped living conditions increase the risk of spreading the disease.
When infected people begin to show symptoms, usually one to four days after infection, they often experience sudden and intense headaches, fever, nausea, vomiting, sensitivity to light, and stiffness of the neck.
Although anyone of any age can become infected with meningitis, babies and children are particularly susceptible.
Diagnosing meningitis in the settings in which we work is often difficult as clinical examination is required - and quickly.
A painful lumbar puncture is needed for the examination of spinal fluid and sometimes the bacteria can be seen under a microscope.
However, the diagnosis is confirmed by growing bacteria from spinal fluid or blood. These diagnostic tests allow for further tests to see how effective certain antibiotics will be for the patient.
A range of antibiotics can treat the infection, including penicillin, ampicillin, chloramphenicol and ceftriaxone. Under epidemic conditions in Africa in areas with limited health infrastructure and resources, ceftriaxone is the drug of choice
However, timely mass vaccinations are the most effective means of limiting the spread of epidemics.
In 2010, a new meningococcal A conjugate vaccine was introduced in Africa and, as of November 2017, more than 280 million people had been vaccinated.
According to the WHO, this has led to a 58 percent drop in cases and reduced the risk of epidemics by 60 percent. Maintaining high immunisation coverage is expected to eliminate meningococcal A epidemics from the meningitis belt completely.
However, other strains are still causing epidemics. Conjugate vaccines against multiple meningococcus strains (ACWY) are very expensive and in short supply, and are therefore impossible to use for wide-scale preventive campaigns.
A new meningococcus conjugate vaccine against the ACWYX strains is currently being developed and expected to be available at an affordable price in 2021 or 2022.