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What is Bacterial Meningitis?

Bacterial meningitis is a serious illness. It can, for some, lead to death in a matter of hours. That said, most people do recover. Recovery isn’t always straightforward, though, and can result in permanent problems and disabilities, like hearing loss, learning disabilities, brain damage, and loss of limbs.

In terms of statistics, in 2018/19 one in 100,000 people contracted bacterial meningitis overall. Of all cases, 16% were in young people aged between 15 and 24 and 49% were in people aged over 25. As for fatalities, between 4% and 10% of children who contract bacterial meningitis will die. This figure is 25% for adults. Complications are also common and affect up to 30% of people.

What is bacterial meningitis?

Bacterial meningitis is an infection and inflammation of the meninges – the lining that protects and surrounds the spinal cord and brain. This inflammation is caused by a bacterial infection and is life-threatening.

The illness is most prevalent in the young – particularly those aged between 15 and 24 years of age. Most cases of bacterial meningitis are isolated cases, but the meningitis-causing bacteria can be spread between people in close proximity.

What causes bacterial meningitis?

There is no single strain of bacteria that causes meningitis.

Here are some of the most common meningitis-causing bacteria:

  • Streptococcus pneumoniae
    This is a significant pathogenic bacterium and has been studied extensively. It was first recognised as a cause of pneumonia in the late 1800s. The bacteria lives in the respiratory tract, nasal cavity and sinuses asymptomatically in healthy people. But when people have a weaker immune system – like young children or the elderly – it can become pathogenic and disease-causing.
    As well as causing pneumonia, it causes meningitis, and sepsis.
  • Group B Streptococcus
    This bacterium is present in 35% of healthy women’s gastrointestinal and reproductive tracts and is most commonly known for transmitting infection to newborns at birth, causing meningitis and/or sepsis. It remains the primary cause of neonatal sepsis.
  • Neisseria meningitidis
    This is often referred to as ‘meningococcus’. It causes meningitis as well as other types of meningococcal disease like a life-threatening form of sepsis called meningococcaemia. Around one in ten adults carry these bacteria asymptomatically in a part of their respiratory tract called the nasopharynx.
    This is the primary cause of bacterial meningitis and is the only type to cause an epidemic, though this mainly happens in Asia and Africa. It occurs endemically throughout the world.
  • Haemophilus influenzae
    This bacterium was first referred to in 1892 during a pandemic of influenza. It was described incorrectly as the cause of the disease, which is why it still has the reference to ‘influenza’ in its name.
    These bacteria cause a variety of invasive diseases, usually in children and infants. This includes pneumonia and bloodstream infections as well as meningitis. This bacterium is usually resistant to penicillin.
  • Listeria monocytogenes
    This is a foodborne pathogen and is one of the most virulent of its kind. It causes a range of illnesses but can cause meningitis in newborns born vaginally. It is for this reason that pregnant women are told not to eat certain soft cheeses like camembert and brie because they could be contaminated with this bacterium.
    This can also cause meningitis as well as other disease like encephalitis and pneumonia in others.
  • Escherichia coli
    Also known as E. coli, this is usually responsible for food poisoning. It thrives in fresh faecal matter and is expelled to the environment within faecal matter. Virulent strains of E. coli usually cause severe gastroenteritis, UTIs and meningitis in newborns.
  • Mycobacterium tuberculosis
    This bacterium was discovered in the late 19th century by Robert Koch. It is a pathogenic bacterium that is the main cause of tuberculosis. It mostly affects the lungs. It can, however, cause a rare form of bacterial meningitis called TB meningitis.
  • Age groups and causes
    Depending on your age, you’re more likely to be affected by a different strain of bacterial meningitis:
    – Newborns are more likely to get meningitis caused by L. monocytogenes, S. Pneumoniae, E. Coli, and Group B Streptococcus.
    – Young children and babies are more likely to contract N. meningitidis, S. pneumoniae, M. tuberculosis, H. influenzae and Group B Streptococcus.
    – Young adults and teens are more likely to contract S. pneumoniae and N. meningitidis.
    – Older adults are more likely to contract L. monocytogenes, Group B Streptococcus, H. influenzae, N. meningitis, and S. pneumoniae.
Hearing loss due to bacterial meningitis

Signs and symptoms of bacterial meningitis

The symptoms of bacterial meningitis are usually acute, have a sudden onset and worsen quickly.

These include:

  • Headache.
  • Fever.
  • Stiff neck.

These are the three main symptoms. However, there are also other symptoms that people can have.

These include:

  • Photophobia (light sensitivity).
  • Nausea.
  • Vomiting.
  • Confusion (altered mental status).

In newborns and babies, symptoms are not always obvious and it’s difficult to detect them.

Instead, you should look out for:

  • Irritability.
  • Inactiveness or slowness.
  • Vomiting.
  • Poor feeding.
  • Abnormal reflexes.
  • A bulging ‘soft spot’ (fontanelle) on the head.

The symptoms of bacterial meningitis will typically develop over three days to a week after the person has been exposed to the bacteria. One exception is TB meningitis. This can develop after a longer time following exposure.

Because bacterial meningitis can cause coma, seizures and death, it’s important to seek urgent medical attention as soon as the disease is suspected.

Pregnancy and meningitis in newborns

Being pregnant increases the risk of contracting L. monocutogenes. The pregnant woman might not have symptoms or might feel like they have a bout of the flu with muscle aches, fever and fatigue.

The biggest concern, however, is that being infected can cause problems with an unborn baby including miscarriage or stillbirth. It can also induce early delivery or a life-threatening newborn meningitis or sepsis.

Another concern for pregnant women is Group B Streptococcus, which is commonly referred to as ‘group B strep’. This can be carried asymptomatically in the vaginal canal and be passed on to a newborn to cause meningitis. If a woman is known to carry the bacteria, she will be given antibiotics during labour. However, routine testing for the bacteria isn’t carried out.

How bacterial meningitis spreads

Some meningitis-causing bacteria (like L. monocytogenes) can spread to people through food. Most, however, are spread from person to person.

How these are spread depends on the bacteria. Some bacteria occur naturally and asymptomatically without infecting their carrier. Despite not becoming sick themselves, carriers can spread this bacterium on to other people.

Here are the different ways in which the meningitis-causing bacteria can spread:

  • E. coli and Group B Streptococcus can be passed on to babies from their mothers during birth.
  • S. pneumoniae, M. tuberculosis and H. influenzae are spread through sneezing and coughing. The expelled bacteria are inhaled by those close by.
  • N. meningitidis is passed through throat or respiratory secretions – i.e., coughs and sneezes as well as saliva. This could be through kissing, coughing or just living together.
  • E. coli is passed on through food preparation when people haven’t washed their hands properly.

How is bacterial meningitis diagnosed?

If meningitis is suspected, a doctor will order tests to confirm. This will include blood tests and a lumbar puncture to collect a sample of the cerebrospinal fluid (CSF). Knowing the strain of bacteria causing the infection is important for treatment.

There might also be other tests ordered including:

  • Urine testing.
  • Swabs of the nose and throat.
  • Brain imaging in the form of a CT scan.
Symptoms of bacterial meningitis

How is bacterial meningitis treated?

Firstly, lost of strains of meningitis can be prevented by a vaccination. This is the most effective way of protecting people from certain strains of bacterial meningitis.

There are different strains that can be vaccinated against:

  • N. meningitidis.
  • S. pneumoniae.
  • Haemophilus influenzae serotype b (Hib).

Like any vaccination, these won’t always be 100% effective. They also don’t protect people from every type of bacterial meningitis. This is why vaccinated people can still contract bacterial meningitis.


Another form of prevention is prophylaxis, which is preventative healthcare. When a patient has contracted bacterial meningitis, people close to them might be offered a course of antibiotics to prevent them from getting ill.

Both meningococcal disease and bacterial meningitis are notifiable diseases. Close contacts are usually informed but the risk to them is low. The highest risk period is during the first week after the case has been diagnosed.

Regardless of vaccination status, prophylactic treatment is considered for all close contacts, including:

  • Those who have had prolonged contact due to living with the patient in the seven days before the illness developed.
  • Those who have been directly exposed to the patient and their respiratory tract secretions when they were admitted.

Prophylactic treatment should ideally be administered within 24 hours of the initial case being diagnosed.

Bacterial meningitis risk factors

There are factors that increase your risk of contracting bacterial meningitis.

The following are all considered to be risk factors:

  • Age: Newborns, babies and infants are all at a greater risk of contracting bacterial meningitis.
  • Groups: When people gather together in large groups – e.g., a dormitory – infectious diseases are more likely to spread.
  • Medical conditions: Certain medications, surgical procedures and medical conditions increase a person’s risk of getting bacterial meningitis. Being infected with HIV, having your spleen removed, or having a leak of cerebrospinal fluid, all increase the risk of getting bacterial meningitis.
  • Work with pathogens that cause meningitis: A microbiologist who routinely works with bacteria that cause meningitis will be at an increased risk of getting the disease.
  • Travel: Those who travel could have a higher risk of contracting N. meningitidis depending on their destination. For example, sub-Saharan African in the dry season, Mecca during the pilgrimage. Also, lots of countries still have high levels of TB, which means there is an increased risk there.

Is bacterial meningitis contagious?

Anyone who has been in close contact with someone who has bacterial meningitis could need preventative treatment. It is rare for the disease to be passed from person to person, but it does happen. Anyone who has only had casual contact is likely to be unaffected.

Vaccinations for bacterial meningitis

There are several preventative vaccinations that are given to people in the UK to prevent against bacterial meningitis. It’s important to recognise that some of the strains of bacteria that cause meningitis aren’t covered by a vaccination.

Here are the vaccinations available:

  • MenB – This protects against meningococcal group B bacteria. It is given at 8 weeks old, 16 weeks old and 12 months old.
  • 6-in-1 vaccine – This protects against Haemophilus influenzae type b (Hib) as well as other diseases. It is given at 8 weeks old, 12 weeks old and 16 weeks old.
  • Pneumococcal vaccine – This protects against pneumococcal bacteria and is given at 12 weeks old and 12 months old.
  • Hib/MenC – This is given at 12 months old and protects against meningococcal group C bacteria.
  • MenACWY – This is given at 14 years old. It protects against meningococcal meningitis caused by bacteria groups A, C, W and Y.

How the vaccines work

The meningitis vaccines work by encouraging the body to produce antibodies for the bacteria that cause meningitis. These antibodies mean that should the body come into contact with the bacteria in the future, you should be able to fight off the disease. They are proteins that destroy or neutralise the disease-carrying toxins and organisms.

There have been over 90 different pneumococcal strains of bacteria identified but the majority of these won’t cause a serious infection.

Having vaccine

Vaccine effectiveness

Generally speaking, children will respond well to the vaccines. When they were introduced as a schedule on the NHS, there was a considerable reduction in the number of people affected by pneumococcal disease.

The vaccine given to older children is considered around 50% to 70% effective at disease prevention. The vaccines do not contain live organisms and so they won’t cause the disease that they are designed to protect against.

Are there any people who shouldn’t have the vaccine?

There are only very few people who shouldn’t have a vaccine and that’s usually if they’ve had a bad reaction to one in the past. If there has been a severe allergic reaction like anaphylaxis to any vaccine ingredient, the person won’t be able to have it. If reactions are mild, it’s still advisable to have the vaccine.

If there is a mild illness at the time of the injection, this is ok, but with a serious illness that involves a high temperature, it’s advisable to wait until the person is feeling better.

It’s also fine for women who are pregnant or breastfeeding to have the vaccine, though some pregnant women prefer to wait until the baby is born.

Vaccine side effects

Like any vaccine, there might be some side effects to watch out for. This might be a little swelling or hardness at the injection site, redness where the needle went into the skin, etc. There are no serious side effects apart from anaphylaxis in those allergic to one or more of the vaccine’s ingredients.

Final thoughts

Bacterial meningitis is the most dangerous type of meningitis. Unlike viral meningitis which often gets better on its own, bacterial meningitis gets worse quickly and needs treatment in hospital. It is more common among young people but anyone at any age can get the disease. As complications can occur and it can be fatal, swift diagnosis and treatment is required.

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About the author

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Louise Woffindin

Louise is a writer and translator from Sheffield. Before turning to writing, she worked as a secondary school language teacher. Outside of work, she is a keen runner and also enjoys reading and walking her dog Chaos.

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