Meningitis is inflammation of the meninges, the lining surrounding the brain and spinal cord. It can be caused by bacteria, viruses, fungi and amoeba. One of the most common forms is meningococcal meningitis. Meningococcal infections can also cause septicaemia (blood poisoning). Viral meningitis is less severe than bacterial meningitis, which is always associated with serious and severe illness.

The general geographical pattern here is for urban areas to have higher rates. These urban areas are surrounded by neighbourhoods with rates near the national average, which in turn lie next to more suburban and rural areas with low rates. Sometimes the poorer parts of cities can be seen more often to have higher rates, such as in the east of London.

The lowest rates tend to be found in the more remote and/or rural parts of Britain. Meningitis is an infectious disease and can cluster where people live in close proximity, for example among students living in halls of residence. There are, however, some obvious anomalies to this general pattern. Much of Birmingham has rates around the national average, with rates as low as half the average in the Sutton area. Similarly, the eastern half of Dundee, parts of Leeds, and much of Norwich have lower than average rates. Thirty per cent of deaths from meningitis were of children and infants below the age of five.

Meningitis can kill, sometimes within hours, or cause permanent brain damage. The brain damage can often affect subsequent mental ability severely; it may also cause spasticity or paralysis of one or more limbs. Other long-term effects can include recurrent epileptic fits and deafness. Several bacteria can cause meningitis, and vaccines are available for some of them. Mortality can be high without the quick use of appropriate antibiotics.

This disease affects males and females equally. Everyone is potentially at risk from meningitis but the very young are most vulnerable. Meningitis tends to be more common where there is overcrowding, poverty and malnutrition.