Haemophilus Influenzae Infections
What is Haemophilus influenzae?
Haemophilus influenzae, or H. influenzae, represents a group of bacteria that may
cause different types of infections in infants and children. H. influenzae most commonly
causes ear, eye, or sinus infections, and pneumonia. A more serious strain of the
bacteria called H. influenzae type b has been nearly abolished in the U.S. due to
the development of an effective vaccine, which has been available since 1988. The
more serious strain was responsible for causing many cases of meningitis (infection
of the membranes that surround the brain) and a life-threatening infection called
epiglottitis (infection of the area of the throat that covers and protects the voice
box and trachea during swallowing). Both meningitis and epiglottitis can be caused
by other bacteria, however. In rare cases, children may still develop H. influenzae
type b infections. This can occur in a child who has not completed his or her series
of immunizations or in older children who did not get the vaccine as an infant.
How is H. influenzae transmitted?
The H. influenzae bacteria live in the upper respiratory tract and are usually transmitted
by close contact with an infected person. Droplets in the air from a sneeze or cough can
be inhaled and may also cause infection.
What are the symptoms of H. influenzae?
The following are the most common symptoms:
Otitis media (middle ear infection). May develop after a child has a common cold caused
by a virus. Symptoms may include:
Trouble sleeping or staying asleep
Tugging or pulling at one or both ears
Fluid draining from ear(s)
Loss of balance
Conjunctivitis. An inflammation of the conjunctiva of the eye. The conjunctiva is
the membrane that lines the inside of the eyelid and also a thin membrane that covers
the actual eye. Symptoms may include:
Sinusitis. Infection in the sinuses. Symptoms may include:
Runny nose or congestion that lasts longer than 10 to 14 days. The discharge may become
thick green, yellow, or blood-tinged.
Occasional daytime cough
Swelling around the eyes
Usually do not complain of headaches if less than 5 years of age
Runny nose or cold symptoms that last longer than 10 to 14 days
Post nasal drip (nasal drainage that travels down the back of the throat)
Facial discomfort (usually over the cheek bones or over the eyes which worsens when
Swelling around the eye (tends to be worse in the morning)
Epiglottitis. Due to the H. influenzae type b vaccine, epiglottitis is very rare in
children and infants. Epiglottitis is an infection of the area of the throat that
covers and protects the voice box and trachea (or windpipe) during swallowing. It
can be fatal if not treated rapidly.
Some children start with an upper respiratory infection, such as a cold. Symptoms
As the infection worsens, these symptoms may appear:
Meningitis. Due to the H. influenzae type b vaccine, meningitis (due to this bacterium) is
very rare in children and infants. Meningitis is an infection of the membranes that
surround the brain and spinal cord. Symptoms may include:
The symptoms of H. influenzae infection may look like other medical conditions. Always
see your child's healthcare provider for a diagnosis. Epiglottitis is life threatening
and requires immediate medical attention.
How is H. influenzae diagnosed?
Your child's healthcare provider may diagnose the illness based on a physical exam
and a medical history. Specific tests will depend on the location of the infection.
In some cases, your child's provider may take a culture of fluid from the eye, ear,
blood, or spinal fluid. In other situations, this may be not be possible and a diagnosis
will be made based on your child's specific symptoms. Other tests may include:
What is the treatment for H. influenzae infections?
Regardless of the location, antibiotics are used to treat infections caused by H.
influenzae. The length of treatment varies depending on the location and severity
of the infection. Other therapy will be aimed at treating the symptoms present.
How can H. influenzae be prevented?
Immunization against type b, which is the most invasive strain of H. influenzae, is
routinely given in a 3 to 4-part series. The vaccine is often referred to as "Hib"
vaccine. Primary doses are given at 2 and 4 months of age or at 2, 4, and 6 months
of age, based on the brand used by the doctor's office. A booster is then given between
12 and 15 months of age. If a child did not get the vaccine and is older than 5 years,
he or she may not be immunized. Other populations that should be encouraged to receive
the vaccine include the following:
Adults and children with sickle cell disease
People without a spleen
Adults and children with weak immune systems
People who are HIV positive