Haemophilus influenzae (H. influenzae) is a group of bacteria that can cause different types of infections in babies and children. H. influenzae most often cause ear, eye, or sinus infections. They also cause pneumonia.

A strain of the bacteria that causes more serious disease is called H. influenzae type b (Hib). The type b strain is now rare in the U.S. because of the Hib vaccine. Before widespread vaccination, significant disease occurred in as many as 130 out of 100,000 kids. That rate is now less than 1 out of 100,000 children. If fewer children are vaccinated against Hib, serious cases will increase. The type b strain is particularly dangerous because it can cause infection of the membranes that surround the brain (meningitis), which can be life-threatening or lead to serious disability after recovery. Hib can also cause a life-threatening infection called epiglottitis. This is infection of the part of the throat that covers and protects the voice box (larynx) and windpipe (trachea) while swallowing. In rare cases, a child may still get an Hib infection despite getting a vaccine. This is more likely to occur in a child who hasn't finished the series of vaccines. Or it can occur in an older child who didn't get the vaccine as a baby. Children who travel to other countries may also be at risk. This is because not all children around the world get the Hib vaccine. Due to vaccination, most cases of H. influenzae that occur today are due to the less serious, non-type b strains of the bacteria.

The H. influenzae bacteria live in the nose, sinuses, and throat. They are often spread by close contact with an infected person. Droplets in the air from a sneeze or cough can be breathed in. These may also cause infection.

Symptoms can be a bit different for each child. Below are the most common symptoms.

This may occur after a child has a common cold caused by a virus. Symptoms may include:

• Abnormal irritability
• Trouble sleeping or staying asleep
• Tugging or pulling at one or both ears
• Fever
• Fluid draining from an ear or ears
• Loss of balance
• Hearing problems
• Ear pain
• Loss of appetite

This is 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 eyeball. Symptoms may include:

• Eye redness
• Swelling
• Fluid from one or both eyes
• Burning feeling of the eyes
• Eyes sensitive to light (photophobia)

This is an infection of the sinuses. Symptoms in younger children may include:

• Runny nose that lasts longer than 10 to 14 days and nasal fluid may become thick green, yellow, or blood-tinged
• Nighttime cough
• Occasional daytime cough
• Swelling around the eyes

Symptoms of sinusitis in older children may include:

• Runny nose or cold symptoms that last longer than 10 to 14 days
• Nasal fluid that drains down the back of the throat (postnasal drip)
• Headache
• Pain over the cheekbones or over the eyes that's worse when leaning over (sinus pain)
• Bad breath
• Cough
• Fever
• Sore throat
• Swelling around the eye that's worse in the morning

This is an infection of the part of the throat that covers and protects the voice box and windpipe when swallowing. Epiglottitis is a medical emergency. It can be fatal if not treated rapidly. Due to the Hib vaccine, epiglottitis is very rare in children and babies.

Symptoms may include:

• Suddenly getting a very sore throat
• Fever
• Muffled voice
• No cough
• Shortness of breath

As the infection gets worse, symptoms may include:

• Drooling
• Inability to talk
• Leaning forward while sitting
• Breathing with mouth open
• Trouble breathing

This is an infection of the membranes that surround the brain and spinal cord. Because of the vaccine, meningitis caused by H. influenzae is very rare in children and babies. Symptoms in children older than 1 year may include:

• Neck or back pain, especially when moving the chin toward the chest
• Headache
• Upset stomach and vomiting
• Neck stiffness
• Eyes sensitive to light

In babies, symptoms are more general and may include:

• Irritability
• Sleeping all the time
• Feeding problems, such as refusing a bottle
• Crying when picked up or being held
• Crying that won't stop
• Bulging soft spot (fontanelle)
• Behavior changes
• Fever
• Not bending the neck when moving or playing with a toy

Many of these symptoms may be caused by other health problems. Have your child see their doctor for a diagnosis.

The doctor will ask about your child's symptoms and health history. They will give your child a physical exam. Your child may also have tests, such as:

• Testing of a small sample of fluid from the eye, ear, blood, or spinal canal to check for signs of the bacteria
• Blood tests to check for signs of the bacteria
• Chest or neck X-ray
• CT scan

Antibiotics are used to treat infections caused by H. influenzae. The length of treatment varies depending on where the infection is and how serious it is. Other treatment is done to ease symptoms. Talk with your child's doctor about the risks, benefits, and possible side effects of all medicines.

Vaccines against H. influenzae type b are routinely given in a 3- or 4-part series. The vaccine is often called the Hib vaccine. The first doses are given at ages 2 and 4 months or at ages 2 months, 4 months, and 6 months. A booster is then given between ages 12 and 15 months. If a child at average risk hasn't had the vaccine and is older than 5 years, they do not need to be vaccinated. The vaccine may be recommended for older children with conditions that put them at higher risk, such as:

• Sickle cell disease
• No spleen (asplenia)
• A weak immune system from cancer or following a bone marrow transplant
• HIV

Contact the doctor if your child has:

• Symptoms that don't get better, or get worse
• New symptoms

• Haemophilus influenzae (H. influenzae) is a group of bacteria that can cause different types of infections in babies and children.
• H. influenzae most often cause ear, eye, or sinus infections. They also cause pneumonia.
• A more serious strain of the bacteria, called H. influenzae type b (Hib), is rare in the U.S. because of the Hib vaccine.
• The H. influenzae bacteria are often spread by close contact with an infected person. Droplets in the air from a sneeze or cough can be breathed in and may also cause infection.
• Antibiotics are used to treat infections caused by H. influenza.
• Vaccines against Hib are routinely given to children.

Tips to help you get the most from a visit to your child's doctor:

• Know the reason for the visit and what you want to happen.
• Before your visit, write down questions you want answered.
• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you for your child.
• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are and when they should be reported.
• Ask if your child's condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if your child does not take the medicine or have the test or procedure.
• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your child's doctor after office hours, and on weekends and holidays. This is important if your child becomes ill and you have questions or need advice.