Hemophilus influenzae type b (Hib)

Hemophilus influenzae type b (Hib) is a bacterium that can cause a life-threatening infection, especially in young children. It can lead to serious conditions such as meningitis (inflammation of the membranes covering the brain) and epiglottitis (inflammation of the flap at the top of the windpipe). These illnesses can develop very quickly and may need urgent medical attention.

Despite its name, Hib is a bacterium and is not a form of influenza (the flu).

How Hib spreads#

Hib bacteria live in the nose and throat of many healthy people without causing illness. There are several types of Hemophilus influenzae bacteria, and infection with the type b strain can cause a range of conditions in vulnerable people, some of which are medical emergencies.

The infection spreads mainly through person-to-person contact with infected droplets, such as coughing or sneezing, or contact with secretions from the nose and throat of an infected person.

The usual time between contact with the bacteria and the start of illness is around two to four days. A person with Hib remains infectious for as long as the bacteria stay in the nose or throat. Generally, 24 to 48 hours of appropriate antibiotic treatment is needed to clear the infection.

Why immunization matters#

Before Hib immunization became routine, Hib was a common cause of life-threatening infection in children under five. Routine immunization has been highly effective in reducing this disease. Children under five and people at increased risk of Hib infection should still be immunized.

Symptoms#

Symptoms of Hib infection can include:

• severe headache
• stiff neck
• convulsions (fits) or seizures
• severe drowsiness or difficulty waking up
• loss of consciousness
• difficulty breathing

Seek urgent medical attention if you suspect your child has any of these symptoms, particularly difficulty breathing.

Complications#

If a child is not immunized and catches Hib, they could develop:

• Meningitis – infection of the membrane covering the brain. Signs include fever, stiff neck, drowsiness, irritability and refusal of food.
• Epiglottitis – inflammation of the flap at the top of the windpipe, which can block a child’s breathing. Signs include severe breathing difficulty, fever, restlessness and irritability.
• Pneumonia – lung inflammation, with fever, cough, chest pain and breathing problems such as shortness of breath.
• Septic arthritis – joint infection, with joint pain, swelling and reduced movement.
• Cellulitis – infection of the tissue under the skin, often on the face.

These complications can develop quickly. If left untreated, a child can become critically ill in a short period of time.

Diagnosis#

Because other bacteria can cause similar infections, it is important to test specifically for Hib. An emergency diagnosis of a life-threatening illness is usually based on the rapid onset of symptoms in a child who was previously well.

Diagnosis may include:

• a physical examination
• a blood test
• a test of the fluid around the spine (cerebrospinal fluid), collected with a needle (lumbar puncture)
• tests of other specimens

Treatment#

Depending on the illness, treatment may include:

• admission to hospital
• a course of appropriate antibiotics
• intensive care for a child with epiglottitis
• a breathing tube to help a child breathe, if needed

If your child has a Hib infection, keep them away from childcare or school until a course of appropriate antibiotics is completed and a doctor has confirmed they are no longer infectious. In some situations, people who live with someone who has a Hib infection may need preventive antibiotics; a doctor or health authority will advise when this is needed.

Immunization against Hib#

Immunization is the best protection against Hib infection and is recommended for all infants and young children, as well as for anyone with a specified medical risk condition. Hib vaccine is usually given as part of a combined vaccine that also protects against diseases such as diphtheria, tetanus, pertussis (whooping cough), hepatitis B and polio.

Many immunization programs schedule Hib vaccine as a series of doses in infancy, with a booster dose in the second year of life. Catch-up doses are available for children who have not had previous doses. A single dose of Hib vaccine is also recommended for anyone who does not have a spleen, and people who have had a stem cell transplant are recommended to receive doses of the vaccine. Ask your doctor or immunization provider about the schedule that applies where you live.

Before immunization#

Before immunization, tell your doctor or nurse if you (or your child):

• are unwell on the day, for example with a temperature over 38.5°C (101.3°F)
• have had a serious reaction to any vaccine in the past
• have had a severe allergy to anything
• are pregnant – Hib vaccine is not generally recommended during pregnancy

Side effects of the vaccine#

Vaccines that protect against diphtheria, tetanus, Hib and other infectious diseases (including the combined six-in-one, four-in-one, three-in-one and two-in-one vaccines) are effective and safe, although, like all medicines, they can have unwanted side effects. Reactions are uncommon and usually mild, and may include:

• being unsettled, irritable, tearful or generally unhappy
• drowsiness or tiredness
• soreness, redness, itching, swelling or burning at the injection site for one to two days
• a low-grade fever
• muscle aches, if the vaccine also protects against polio

Most reactions are mild and short-lived, usually occurring in the first one to two days after vaccination.

Managing side effects#

Specific treatment is not usually needed. You can help your child feel more comfortable by:

• giving extra fluids to drink
• not overdressing a child or baby who feels hot

Routine use of paracetamol (acetaminophen) after vaccination is not recommended, but if a fever is present, paracetamol can be given. Check the label for the correct dose, or ask your pharmacist, especially when giving it to children.

Sometimes a small, hard lump (nodule) forms at the injection site and may last for some weeks or months. This is not a cause for concern and needs no treatment.

When to seek help#

If a reaction after immunization is unexpected, persistent or severe, or if you are worried about yourself or your child afterwards, see your doctor or immunization nurse as soon as possible, or go directly to a hospital. It is also important to seek advice if you or your child are unwell, as this may be due to another illness rather than the immunization.

There is a very small risk of a serious allergic reaction (anaphylaxis) to any vaccine. This is why you are advised to stay at the clinic for at least 15 minutes after immunization, in case further treatment is needed. Serious reactions following immunization can be reported to your immunization provider or health authority.

Key points#

• Hib is a bacterium that can cause life-threatening infections such as meningitis, epiglottitis and pneumonia, especially in young children.
• Despite its name, Hib is not a form of the flu.
• Seek urgent medical attention if you suspect your child has Hib symptoms, particularly difficulty breathing.
• Generally, 24 to 48 hours of appropriate antibiotic treatment is needed to clear the infection.
• People who live with someone who has Hib may sometimes need preventive antibiotics.
• Immunization is the best protection and is recommended for all infants and young children.

Where to get help#