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What is Haemophilus influenzae?

Haemophilus influenzae, or H. influenzae, is a group of bacteria that cause different types of infections in infants and children. H. influenzae most commonly causes ear, eye, or sinus infections and pneumonia. In rare cases, your child may develop a more serious strain of the bacteria, called H. influenzae type b (Hib) infections. This type has been nearly abolished in the United States thanks to the Hib vaccine. H. influenzae infections spread from child to child by direct contact or through the air. The good news is that these infections can be successfully treated with antibiotics.

Types of Haemophilus influenzae

  • otitis media 
    • middle ear infection
    • may develop after a child has a common cold caused by a virus
  • conjunctivitis 
    • inflammation of the membrane that lines the inside of the eye and also a thin membrane that covers the actual eye
  • sinusitis 
    • infection in the sinuses
  • epiglottitis 
    • prevented by Hib vaccine
    • very rare in children and infants
    • life-threatening
    • infection of the area of the throat that covers and protects the windpipe
  • meningitis 
    • prevented by Hib vaccine
    • very rare in children and infants
    • infection of the membranes that surround the brain and spinal cord

Haemophilus Influenzae Infections | Symptoms & Causes

What causes Haemophilus influenzae?

The H. influenzae bacteria live in the upper respiratory tract and are usually transmitted by close contact with an infected individual. Droplets in the air from a sneeze, cough, or close conversation can be inhaled and may also cause infection.

What are the symptoms of Haemophilus influenzae?

Symptoms vary depending on the specific infection:

  • for otitis media (middle ear infection)
    • unusual irritability
    • difficulty sleeping or staying asleep
    • tugging or pulling at one or both ears
    • fever
    • fluid draining from ear(s)
    • loss of balance
    • hearing difficulties
    • ear pain
    • nausea and vomiting
    • diarrhea
    • decreased appetite
    • congestion
  • for conjunctivitis
    • redness
    • swelling
    • drainage from one eye or both eyes
    • burning of the eyes
    • sensitivity to light
  • for sinusitis in younger children
    • runny nose that lasts greater than seven to 10 days
    • thick green or yellow discharge
    • nighttime cough
    • occasional daytime cough
    • swelling around the eyes
  • for sinusitis in older children
    • runny nose or cold symptoms that last greater than seven to 10 days
    • complaints of drip in his/her throat from his/her nose
    • headaches
    • facial discomfort
    • bad breath
    • cough
    • fever
    • sore throat
    • swelling around the eye (tends to be worse in the morning)
  • for epiglottitis
    • upper respiratory infection, such as a cold
    • quick onset of a very sore throat
    • fever
    • muffled voice
    • no cough
    • drooling
    • unable to talk
    • child sits leaning forward
    • child keeps his or her mouth open
  • for meningitis in infants
    • irritability
    • sleeping all the time
    • refusing a bottle
    • cries when picked up or being held
    • inconsolable crying
    • bulging fontanelle (or soft spot)
    • behavior changes
  • for meningitis in children older than 1 year
    • neck and/or back pain
    • headache
    • nausea and vomiting
    • neck stiffness

Can you prevent Haemophilus influenzae?

Immunization with the Hib vaccine can help prevent Haemophilus influenzae type b disease and meningitis. The Hib vaccine is recommended for infants at 2, 4, 6, and 15 to 18 months.

Haemophilus Influenzae Infections | Diagnosis & Treatments

How is Haemophilus influenzae diagnosed?

Your child's doctor may diagnose the illness based on an examination and a medical history. Specific tests will depend on the location of the infection. In some cases, your doctor may take:

  • a culture of fluid from the eye, ear, throat, or spinal fluid
  • chest or neck x-ray
  • blood tests

How is Haemophilus influenzae treated?

Antibiotics may be used to treat H. influenzae infections. The length of treatment varies depending on the location and severity of the infection.

Haemophilus Influenzae Infections | Programs & Services