What causes meningitis and septicaemia?

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.
In the UK and Ireland, meningococcal vaccines are routinely available for high risk groups that protect against all 5 of the most common disease causing strains.
Download our meningococcal meningitis and septicaemia factsheet

Vist our partnership with the Global Meningococcal Intiative for reports on the picture of meningococcal meningitis and septicaemia in the rest of the world.
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.
Pneumococcal vaccines are routinely available for high risk groups.
Download our pneumococcal meningitis factsheet 
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%.
Download our Hib meningitis factsheet

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.

There is currently no vaccine available that protects against GBS meningitis and septicaemia.  There is a vaccine under development however, and it is hoped that in future women will be able to be immunised in pregnancy to protect newborns from this type of meningitis.
Download our GBS meningitis and septicaemia factsheet

Jane Plumb, Chief Executive, Group B Strep Support talks about the long-term affects of GBS at MRF's 2017 conference​

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.

Download our GAS infection factsheet


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.

Download our E.coli meningitis and septicaemia factsheet


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, unpastuerised milk and certain types of cheese.

Download our Listeria meningitis factsheet


Salmonella meningitis is rare and mostly affects newborn babies.

Download our Salmonella meningitis factsheet


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.

Download our TB meningitis factsheet

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

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


Matthew Willis talks about the effect that severe brain damage caused by pneumococcal meningitis has had on his son, Sam, and his family

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.

More about viral meningitis


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

Download our fungal meningitis factsheet


Some types of meningitis causing bacteria are so rare that we only see one or two cases per year.  Some of these are listed in our rarer causes of bacterial meningitis factsheet.

Download our rarer causes of bacterial meningitis factsheet

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