Meningitis is an infection of the meninges, the lining around the brain and spinal cord.
It can be caused by different bacteria and viruses, although bacterial infections are usually more serious. Currently vaccines are given to prevent strains from Men C, Haemophilus Influenzae and Pneumococcal on the NHS.
One of the bacteria which causes meningitis is called Neisseria meningitidis, also known as the meningococcus. This bacteria commonly lives harmlessly in people's throats, but can cause devastating disease if it gets into the blood or spinal fluid. There are different types of this bacteria and the most common is known as type B - what is often referred to as "meningitis B", or MenB.
MenB most commonly affects children under the age of one. In children over the age of four the disease is rare and the vaccine for the NHS is not cost effective.
There is also a second peak in adolescence.
non-blanching rash "doesn't disappear when pressed with a glass"
With early diagnosis and antibiotics, most people will make a full recovery. But around one in ten people infected will die and up to a quarter will have significant after effects, such as hearing loss, amputation, epilepsy or learning difficulties.
Until recently, there was no vaccine against MenB. But in September 2015, the UK was the first country in the world to introduce a new MenB vaccine - Bexsero, produced by GlaxoSmithKline - into the routine NHS childhood immunisation programme.