What causes meningitis and septicaemia?

Fast facts

  • Bacteria, viruses and fungi can cause meningitis and septicaemia if they invade the body.
  • Although there are vaccines which prevent some types, not all causes are vaccine preventable so it’s vital to be aware of the symptoms.

Bacterial meningitis and septicaemia

Bacterial meningitis and septicaemia are serious, life threatening illnesses.  

At least 50 kinds of bacteria can cause meningitis, but the main types are:  

Meningococcal bacteria are the most common cause of bacterial meningitis and septicaemia in the UK and Ireland.


Babies and children under the age of 5 are at the highest risk, but there is a secondary peak of disease amongst teenagers.


There are several different groups of meningococcal bacteria that cause disease. The most common disease causing groups are meningococcal A, B, C, W and Y. These are commonly referred to as MenA, MenB, MenC, MenW and MenY.


Pneumococcal meningitis is the second most common cause of bacterial meningitis and septicaemia in the UK and Ireland, and in some countries is the most common cause.


Most cases of pneumococcal meningitis are in children under two years old, adults over the age of 65 and in those with medical problems that put them at increased risk of disease.


Pneumococcal meningitis can be severe and has a higher risk of death and long term brain damage than most other causes of bacterial meningitis.

Vaccines that protect against Hib meningitis are routinely given to babies in many countries.


Since the Hib vaccine was introduced in the UK in 1992, cases have dropped by over 90%.

This is the main cause of meningitis and septicaemia in newborn babies.


It can be transmitted from mother to baby before or during birth, or through contact with adults who handle the baby.


An estimated 20 –30 % of pregnant women carry GBS bacteria in the bowels or vagina, but 99% of babies born to mothers who carry the bacteria are perfectly healthy.



GAS bacteria are commonly found on the surface of the skin and in the throat.


These bacteria commonly cause mild throat, skin, ear and sinus infections in both adults and children.


More rarely these bacteria cause an invasive infection where they penetrate deeper into the tissues and organs of the body causing more serious disease.

This bacteria is an important cause of meningitis in newborn babies and people with medical conditions that put them at increased risk.


E.coli is a much greater problem in developing countries.

Listeria meningitis occurs mainly in newborns, elderly people and those with weakened immune systems.


It can be passed from mother to baby during pregnancy or labour.


Mothers can become infected with this type of bacteria by eating products contaminated with listeria. This is why women are advised not to eat certain foods in pregnancy such as pâté, unpasteurised milk and certain types of cheese.

Salmonella meningitis is rare and mostly affects newborn babies.

This is a rare cause of meningitis.

Diagnosis of TB meningitis can be difficult because the onset of illness is not as sudden as with other types of bacterial meningitis.

Some of those bacterial types are more likely to affect newborn babies:

  • Group B Streptococcal (GBS)
  • E. coli
  • Listeria
  • Salmonella

Other causes of meningitis and septicaemia

Viral meningitis is almost never life-threatening and viruses rarely cause septicaemia.


Since people often recover from viral meningitis without medical treatment, it is difficult to measure how many cases of viral meningitis cases occur each year, but it is probably much more common than bacterial meningitis.

Fungal meningitis is very rare in the UK and Ireland but is serious. It usually only affects people with weakened immune systems.

Some types of meningitis causing bacteria are so rare that we only see one or two cases per year. .

Meningitis and septicaemia can kill in hours - know the symptoms.
There are safe and effective vaccines available that that protect against the most common causes of life-threatening bacterial meningitis and septicaemia

Detailed information about the after effects of meningitis

Dr Fiona McGill answers one of our most frequently asked questions.
Type - Bacterial (meningococcal)
Age group - Adult
Outcome - Bereavement

"I couldn’t really get my head around this, I had literally seen her 48 hours ago and she was walking around completely fine."
Type - Bacterial (pneumococcal)
Age group - Toddler
Outcome - Bereavement

"We took the decision to turn off all her machines and let her die peacefully in our arms"
Type - Viral
Age group - Adult
Outcome - Full recovery

"They told me it would take a couple of weeks to feel better. It truly has taken almost two months."
Connect families affected by meningitis so they don’t feel alone
Connect families affected by meningitis so they don’t feel alone
£58 funds one support worker to attend our ‘Meningitis Meet-Ups’ – a chance for families affected by meningitis to meet each other for informal peer support.
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Membership and support

The MRF Membership and Support team are here for you for any questions you might have about meningitis and septicaemia and their effects on you, or your family and friends.

Tel: Helpline UK 080 8800 3344 Ireland 1800 41 33 44