Published Tue, 2012-02-14 14:19; updated 4 years ago.

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Meningitis is an infection of the meninges (the protective membranes that surround the brain and spinal cord).

The infection can be caused by bacteria or a virus, and leads to the meninges becoming inflamed or swollen. This can damage the nerves and brain.

Meningitis causes symptoms such as:
•    severe headache
•    vomiting
•    high temperature (fever) of 38ºC (100.4ºF) or over
•    stiff neck
•    sensitivity to light
•    a distinctive skin rash (although not everyone will develop this)

Symptoms can differ in young children and babies. See Meningitis - symptoms  for more information.

Bacterial meningitis is very serious and should be treated as a medical emergency. If the bacterial infection is left untreated, it can cause severe brain damage and infect the blood (septicaemia) .

In 2008 and 2009 in England and Wales, around 1,166 cases of meningitis were caused by the Neisseria meningitidis bacteria.

The number of cases has decreased in recent years because of a successful vaccination programme that protects against many of the bacteria that can cause meningitis.

Bacterial meningitis is most common in children under five years old, and in particular in babies under the age of one. It is also common among teenagers aged 15 to 19 years.

Viral meningitis is the most common and less serious type of meningitis. It is difficult to estimate the number of cases of viral meningitis because the symptoms are often so mild that they are mistaken for flu.

Viral meningitis is most common in children and is more widespread during the summer months.

Viral meningitis usually gets better within a couple of weeks, with plenty of rest and painkillers for the headache.

Bacterial meningitis is treated with antibiotics. Treatment will require admission to hospital, with severe cases treated in an intensive care unit so that the body's vital functions can be supported.

Several decades ago, almost everyone who had bacterial meningitis would die. Nowadays, deaths are mainly caused by septicaemia rather than meningitis.

Meningococcal disease (the combination of meningitis and septicaemia) causes death in around one in 10 cases.

Up to a quarter of people may experience complications, such as hearing loss, after having bacterial meningitis (see Meningitis - complications)

The best way to prevent meningitis is by ensuring that vaccinations are up to date. See the Vaccination planner for more information about all the different types of vaccines that are available and when they should be given.

Due for review February 2013

NHS Choices