Haemophilus influenzae meningitis

On this page you’ll find an overview of meningitis caused by Haemophilus influenzae bacteria, including symptoms, treatment and prevention.

  • Haemophilus influenzae (Hi) meningitis is a potentially deadly form of bacterial meningitis.
  • There are six different serotypes of Hi bacteria (types a to f). Haemophilus influenzae type b (Hib) is the most virulent.
  • Widespread rollout of a vaccine against Haemophilus influenzae type b (Hib) has caused a 60% reduction in cases of Hi meningitis globally.1
  • In countries that have high vaccine coverage against Hib, meningitis caused by other serotypes of Haemophilus influenzae are more common.
  • Hib is still an important cause of meningitis in countries with low vaccine coverage rates.

What is Haemophilus influenzae meningitis?

Haemophilus influenzae meningitis is the swelling of the membranes, called meninges, that cover and protect the brain and spinal cord. It's caused by the bacteria Haemophilus influenzae.

There are six different serotypes of Haemophilus influenzae bacteria (types a-f), as well as other Haemophilus influenzae bacteria that are classified as non-typeable. The most virulent strain is Haemophilus influenzae type b (Hib) which causes meningitis in 50-65% of infections.2

Haemophilus influenzae meningitis occurs when the bacteria invade the body and enter the cerebrospinal fluid (CSF), which surrounds and cushions the brain and spinal cord. In the CSF, bacteria can rapidly multiply and release poisons, causing inflammation and swelling in the meninges. This increases pressure on the brain, producing symptoms of meningitis.
 

What are the symptoms of Haemophilus Influenzae meningitis?

The symptoms of Haemophilus influenzae meningitis can progress rapidly, and early diagnosis and treatment will increase the chances of a full recovery.

Symptoms may include:
 
  • Fever.
  • Vomiting.
  • Severe headache.
  • Stiff neck (less common in young children).
  • Dislike of bright lights.
  • Seizures (fits).
  • Confused / delirious.
  • Very sleepy / vacant /difficult to wake.
Symptoms in babies and very young children can be slightly different. Their symptoms may include:
 
  • High temperature (warning: could be normal or low in babies under three months old).
  • Irritability.
  • Vomiting / refusing to feed.
  • A high-pitched cry.
  • A stiff body with jerky movements or else floppy and lifeless.
  • Very sleepy / staring expression / too sleepy to wake up.
  • Tense or bulging soft spot on the top of their head.

Not everyone with meningitis will get all of these symptoms.

People with Haemophilus influenzae meningitis will get worse fast. Check regularly on someone who is unwell and trust your instincts. Get medical help straight away if you or someone you know is seriously ill.

Read more information about the symptoms of meningitis.

How do you get Haemophilus influenzae meningitis?

Haemophilus influenza bacteria can live in the nose and throat of healthy people, and they don’t usually cause symptoms or illness. The bacteria are mainly passed from person to person by sneezing, coughing and close physical contact like kissing.

In some cases the bacteria move to other parts of your body, where they can cause infection. Meningitis occurs if the bacteria invade the membranes and fluid surrounding the brain and spinal cord.

Hi bacteria can also cause many other illnesses such as:
 
  • Otitis media (middle ear infection).
  • Sepsis (also known as blood poisoning and septicaemia).
  • Pneumonia, cellulitis (inflammation of tissue).
  • Osteomyelitis (bone infection).
  • Arthritis.
  • Epiglottitis (inflammation of the back of the throat).
  • Pericarditis (inflammation of the heart lining).

Only a small fraction of people exposed to Hi bacteria become ill.

Who can get Haemophilus influenzae meningitis?

Haemophilus influenza meningitis can affect anyone, but there are certain groups of people that are more at risk than others.

Children younger than five years of age are at highest risk.

Hi meningitis is rare in adults and mainly occurs in those with other factors that make them vulnerable,3 such as:

  • Cerebrospinal fluid (CSF) leakage.
  • Ear, nose and throat (ENT) infections.
  • Weakened immune systems.
Certain populations are at higher risk of disease than others. In the US, American Indian and Alaska Native children under five have a substantially higher incidence of disease caused by Hi bacteria.4

How is Haemophilus influenzae meningitis treated?

Haemophilus influenzae meningitis must always be treated urgently with antibiotics.

Meningitis can kill quickly, so seek immediate medical care if you suspect that you or someone you know have this disease. Prompt recognition and hospital treatment offer the best chance of a good recovery.

When you get to hospital, the doctor may do a lumbar puncture (LP) to help diagnose meningitis. A lumbar puncture involves taking a sample of cerebrospinal fluid from the spinal canal (the space through the back bones which contains the spinal cord). A lumbar puncture is important to confirm the diagnosis of meningitis. It will also show which germ is causing the illness so doctors can choose the most appropriate treatment.

You may be given antibiotics intravenously (directly into the vein). Steroids may also be given to reduce swelling around the brain.

If you’re very unwell, you might be transferred to a special ward in the hospital where you can be regularly monitored by hospital staff. In the UK this is known as an Intensive Care Unit.

What are the after-effects of Haemophilus influenzae meningitis?

It’s important to remember that although Haemophilus influenzae meningitis is a serious illness, with early treatment most people will make a good recovery.

However, some will have permanent after-effects. These are usually due to an acquired brain injury caused by the meningitis. These may include:

  • Learning and intellectual disabilities such as memory loss, lack of concentration or issues with thinking and problem solving.
  • Clumsiness and co-ordination problems.
  • Headaches.
  • Deafness, hearing problems, tinnitus, dizziness or loss of balance.
  • Epilepsy or seizures.
  • Weakness, paralysis or spasms.
  • Loss of sight or vision problems.
  • Hydrocephalus (fluid on the brain).
  • Mental health issues and changes to personality or behaviour.
  • Difficulties with sleep.
  • Fatigue.
  • Anxiety and depression.
Often, the after-effects are temporary or improve over time. But around 30% of survivors will have long-term complications and disability following Hi meningitis. 10-15% of survivors will experience severe neurologic effects.

Long term after-effects of meningitis are usually identified while you’re still in hospital. For very young children it might not be possible to tell if they have any long-term effects until they get older.
Woman in an office speaking on the phone

Physical and emotional recovery from meningitis and its impact can be different for everyone. Support is available if meningitis has affected you or someone you know.

If you are in the UK or Ireland, the Meningitis Research Foundation Support Services team are ready to answer your questions.

If you are outside the UK and Ireland, our member network is the Confederation of Meningitis Organisations (CoMO). CoMO is dedicated to reducing the impact of meningitis globally, with members across the world. It is a great resource for finding support where you live.

Find a CoMO member in your country.

Is there any follow-up care after recovery from Haemophilus influenzae meningitis?

Ideally, you should be given information about what to expect during recovery before you leave the hospital. The follow-up care you receive will be different depending on where you are in the world, and the guidelines that your local doctors follow. You may have further treatment involving different teams of doctors and specialists.

In some countries (including the UK), doctors will arrange at least one follow-up appointment so they can check for longer-term after-effects. This is particularly important for children, as some long-term neurodevelopmental complications can't always be identified immediately after their illness.

Read more about the follow-up care after recovery from meningitis.

Can we prevent Haemophilus influenzae meningitis?

Yes, many cases of meningitis caused by the most virulent type of Haemophilus influenzae, Hib, can be prevented with a vaccine. But no vaccine is currently available to prevent meningitis caused by other serotypes of the bacteria.

Vaccination is the best way to protect against Hib meningitis. The most important thing that anyone can do to prevent Hib meningitis is to make sure they get all their vaccinations.

The World Health Organisation (WHO) recommends that all countries include Hib conjugate vaccines as part of routine infant immunisation programmes. The vaccine not only protects the child who gets vaccinated, but also stops the bacteria from living in their nose and throat. This helps to protect the wider population from the disease by preventing the spread of the bacteria.2

193 out of 194 WHO member states have introduced the Hib vaccine into their routine immunisation schedules. It’s estimated that cases of Hib meningitis have fallen by over 60% globally since the vaccine has been introduced. Hib meningitis has virtually been eliminated from countries with high vaccine coverage. Unfortunately, in countries that have not introduced the vaccine, Hib is still a major cause of serious disease in children.

As there’s no vaccine to protect against all the different serotypes of Haemophilus influenzae that can cause meningitis, it’s important to be aware of the symptoms of the disease.

Can I get a vaccine to protect me against Haemophilus influenzae meningitis?

All countries in the world, except for China, have a Haemophilus influenza type b (Hib) vaccination programme. You can find out about your own country’s immunisation programme on the WHO Immunization Data Portal.

The Hib vaccine is very effective, but no vaccine provides 100% protection. It’s important to know the symptoms of meningitis and trust your instincts. If you are worried, seek medical help.

Vaccination in the UK

In the UK, the Hib vaccine is offered to babies at two, three, and four months of age. This vaccine also helps to protect your child against serious illnesses like polio and whooping cough. A booster dose is also offered at one year of age, which gives longer protection.

Read more about the Hib vaccine.

Frequently asked questions about Haemophilus influenzae meningitis

What is Haemophilus influenzae type b?

Haemophilus influenzae type b (Hib) is a type of bacteria. The bacteria can live in your nose and throat and usually don’t cause any harm. In some cases, Hib bacteria may move to other parts of your body and cause infection. This can range from mild ailments, such as ear infections and minor respiratory illness, to serious illnesses, such as meningitis, sepsis and pneumonia.

What is Haemophilus influenzae type a?

Haemophilus influenzae type a (Hia) is a type of bacteria. It can cause several different kinds of infections, ranging from mild ear infections to potentially life-threatening invasive disease such as meningitis or sepsis.

Invasive disease caused by Hia was once very rare, except in Indigenous populations in North America and Australia. But since 2008, the incidence of invasive disease caused by Hia has increased in the United States, with the highest incidence seen in American Indian and Alaska Native children.6,7 There have also been reports of an increase in invasive Hia cases in Europe, including in England, Italy, Spain, Ireland and Portugal.8,9,10,11,12

What is the survival rate for Haemophilus influenzae meningitis cases?

Most people who get Hi meningitis will survive. Hib is the most common cause of meningitis due to Haemophilus influenzae. Globally, an estimated two out of ten people who develop Hib meningitis will die. In countries without vaccination programs or where access to medical care is limited, as many as six out of ten people who get the disease may die.12

Is Haemophilus influenzae meningitis bacterial or viral?

Haemophilus influenzae meningitis is caused by a type of bacteria called Haemophilus influenzae. There are six different serotypes of Haemophilus influenzae bacteria (types a-f), as well as other Haemophilus influenzae bacteria that are classified as non-typeable. The most virulent strain is Haemophilus influenzae type b (Hib) and causes meningitis in 50-65% of infections.

Am I at risk of spreading or contracting the disease if I have been in contact with a patient with Haemophilus influenzae meningitis?

Haemophilus influenzae can spread to people who have close or prolonged contact with a patient with Haemophilus influenzae meningitis. If you’re a close household contact of someone who has meningitis caused by Hib bacteria, you may need antibiotics to prevent becoming ill and to stop the disease from spreading. 

In the UK, patients who have been ill with Hib meningitis will be given antibiotics to prevent them from carrying the bacteria before they leave hospital. Antibiotics will also be provided to their close household contacts in case they are carrying the bacteria, which will stop them from passing on the bacteria to anyone else.13

It’s important to remember that only a small fraction of people who are exposed to Hi bacteria become ill.

What is Meningitis Research Foundation doing to defeat Haemophilus influenzae meningitis?

Meningitis Research Foundation is part of WHO's Technical Taskforce for the Global Road Map to Defeat Meningitis by 2030. This taskforce aims to achieve higher coverage of Hib vaccines globally by 2030 to protect as many people as possible. They also aim to have at least one vaccine that protects against Hia licensed by 2028 to address high levels of disease in indigenous communities in North America and Australia.

Research we’ve funded has made some important contributions towards achieving the best protection against Hib by highlighting the importance of the booster dose in the UK vaccine schedule.

Read more about Meningitis Research Foundation funded research.
A.
  1. Global Burden of Disease Collaborative Network. Global Burden of Disease Study 2021 (GBD 2021). Seattle, United States: Institute for Health Metrics and Evaluation (IHME), 2024.
  2. World Health Organization. (2013). Haemophilus influenzae type b (Hib) vaccination position paper — July 2013: Introduction. Weekly Epidemiological Record, 88(39), 413-426. https://iris.who.int/handle/10665/242126
  3. Chekrouni, N., Koelman, D. L. H., Brouwer, M. C., van der Ende, A., & van de Beek, D. (n.d.). Community-acquired Haemophilus influenzae meningitis in adults.
  4. Brown, N. E., Blain, A. E., Burzlaff, K., Harrison, L. H., Petit, S., Schaffner, W., Smelser, C., Thomas, A., Triden, L., Watt, J. P., Pondo, T., Whaley, M. J., Hu, F., Wang, X., Oliver, S., & Soeters, H. M. (2021). Racial disparities in invasive Haemophilus influenzae disease—United States, 2008–2017. Clinical Infectious Diseases, 73(9), 1617–1624. https://doi.org/10.1093/cid/ciab449
  5. Sell, S. (1987). Haemophilus influenzae type b meningitis: Manifestations and long-term sequelae. Pediatric Infectious Disease Journal, 6, 775-778.
  6. GBD 2019 Meningitis Antimicrobial Resistance Collaborators. (2023). Global, regional, and national burden of meningitis and its aetiologies, 1990-2019: A systematic analysis for the Global Burden of Disease Study 2019. Lancet Neurology, 22(8), 685-711.
  7. Soeters, H. M., Oliver, S. E., Plumb, I. D., Blain, A. E., Zulz, T., Simons, B. C., Barnes, M., Farley, M. M., Harrison, L. H., Lynfield, R., Massay, S., McLaughlin, J., Muse, A. G., Petit, S., Schaffner, W., Thomas, A., Torres, S., Watt, J., Pondo, T., Whaley, M. J., Hu, F., Wang, X., Briere, E. C., & Bruce, M. G. (2021). Epidemiology of invasive Haemophilus influenzae serotype a disease—United States, 2008-2017. Clinical Infectious Diseases, 73(2), e371-e379.
  8. Bertran, M., D'Aeth, J. C., Hani, E., Amin-Chowdhury, Z., Fry, N. K., Ramsay, M. E., Litt, D. J., & Ladhani, S. N. (2023). Trends in invasive Haemophilus influenzae serotype a disease in England from 2008-09 to 2021-22: A prospective national surveillance study. The Lancet Infectious Diseases, 23(10), 1197-1206.
  9. Giufrè, M., Cardines, R., Brigante, G., Orecchioni, F., & Cerquetti, M. (2017). Emergence of invasive Haemophilus influenzae type a disease in Italy. Clinical Infectious Diseases, 64, 1626-1628.
  10. López-Olaizola, M., Aguirre-Quiñonero, A., Canut, A., et al. (2021). Haemophilus influenzae type a sequence type 23, northern Spain. Emerging Infectious Diseases, 27, 2504-2506.
  11. McElligott, M., Meyler, K., Bennett, D., Mulhall, R., Drew, R. J., & Cunney, R. (2020). Epidemiology of Haemophilus influenzae in the Republic of Ireland, 2010–2018. European Journal of Clinical Microbiology & Infectious Diseases, 39, 2335-2344.
  12. Heliodoro, C. I. M., Bettencourt, C. R., & Bajanca-Lavado, M. P. (2020). Molecular epidemiology of invasive Haemophilus influenzae disease in Portugal: An update of the post-vaccine period, 2011–2018. European Journal of Clinical Microbiology & Infectious Diseases, 39, 1471-1480.
  13. UKHSA Guidance. Revised recommendations for the prevention of secondary Haemophilus influenzae type b (Hib) disease. Updated 4th September 2024. Available from https://www.gov.uk/government/publications/haemophilus-influenzae-type-b-hib-revised-recommendations-for-the-prevention-of-secondary-cases/revised-recommendations-for-the-prevention-of-secondary-haemophilus-influenzae-type-b-hib-disease
Author: Meningitis Research Foundation.
Reviewed by: Ian Alexander, Meningitis Research Foundation Ambassador; Antonio Carlos Ramos e Silva, Associação Brasileira de Combate à Meningite and CoMO member.
Published: 27 December 2024.

Meningitis in your words: real-life stories

Meningitis affects millions of people, in all regions of the world. Through the bravery of sharing personal stories, we bring together people from every region of the world to support one another, so they are empowered to live a life beyond meningitis.
Type - Bacterial (Haemophilus Influenzae type B - Hib)
Age group - Toddler (1-3)
Outcome - Recovery with after effects

"I turned on the nightlight and looked in horror at Herbie."
Type - Bacterial (Haemophilus Influenzae type B - Hib)
Age group - Child 6-12
Outcome - Recovery with after effects

"I want people to be aware of signs and symptoms."
Type - Bacterial (Haemophilus Influenzae type B - Hib)
Age group - Toddler (1-3)
Outcome - Bereavement

Yvonne Stewart talks about the loss of her young son, Jack, to meningitis in 1999.