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Haemophilus Influenzae Type B

• Hib disease is a bacterial illness that can cause a potentially fatal brain infection in young children. Because of the widespread use of effective vaccines against Hib, very few cases are now diagnosed.
• Hib disease is spread through contact with discharges or droplets from the nose or throat of an infected person.
• Hib disease can be treated with antibiotics.
• Immunization with Hib vaccine starting at age 2 months can prevent Hib disease.

What is Haemophilus influenzae type b (Hib) disease?

Haemophilus influenzae type b disease, also called Hib disease, is an illness that can cause a potentially fatal brain infection in young children. Until recently, Hib disease was an important cause of serious, often deadly, infections in children under age 5. However, with the development and widespread use of vaccines against Hib, very few cases are now diagnosed.

What is the infectious agent that causes Hib disease?

Hib disease is caused by Haemophilus influenzae serotype b, a bacterium.

Where is Hib disease found?

The Hib bacterium is widespread in humans. Along with other bacteria, it usually lives in the throat and nose without causing illness. In some cases, though, the bacterium breaks through the body's defenses and causes disease.

How do people get Hib disease?

Hib disease is spread through contact with discharges or droplets from the nose or throat of an infected person. Hib disease can spread from person to person through sneezing, coughing, or speaking closely with an infected person. A person does not have to have symptoms to spread the bacterium.

What are the signs and symptoms of Hib disease?

The most common and severe manifestation of Hib disease is meningitis (inflammation and swelling in the coverings of the brain and spinal cord). Symptoms of meningitis include fever, weakness, vomiting, and a stiff neck. Hib can also cause infection of the lungs, blood, joints, bones, throat, and covering of the heart. Symptoms depend on the part of the body affected.

How soon after exposure do symptoms appear?

The time between exposure and symptoms is usually less than 10 days.

How is Hib disease diagnosed?

Hib disease is diagnosed by blood culture or, more often, by culture of the cerebrospinal fluid.

Who is at risk for Hib disease?

Unvaccinated children under age 5 are at risk for Hib disease. Hib disease occurs most often in children ages 3 months to 2 years. As children grow older, they are less likely to develop Hib disease. Very few cases occur in persons over age 5.

What complications can result from Hib disease?

Meningitis and other serious infections caused by Hib disease can lead to brain damage or death.

What is the treatment for Hib disease?

Treatment with antibiotics should be started immediately to stop the infection from causing brain damage or death.

How common is Hib disease?

Hib disease is now a rare disease because of highly effective Hib vaccines given to infants beginning at age 2 months and the high vaccination coverage of infants and children under age 2 years. Hib disease occurs mainly in under-vaccinated children and in infants too young to have completed the first series of shots.

Is Hib disease an emerging infectious disease?

No. Cases have declined by 96 percent over the past 10 years in the United States. However, getting children vaccinated and guaranteeing that they get the complete series of shots is still a challenge, especially among children with poor access to health care and in areas of the country with significant under-vaccination.

How can Hib disease be prevented?

• Prevent infection in all children -- Hib disease is preventable by immunizing all children under age 5 years with an approved Hib vaccine. Several Hib vaccines are available. The general recommendation is to immunize children with a first dose at 2 months of age and to follow with additional doses based on the schedule for the vaccine being used. If a child under age 5 has missed getting immunized, a health-care provider can give details on the required vaccine dosage and schedule.
• Prevent infection in close contacts of infected children -- Infants and young children who are exposed to a child with Hib disease can be given an antibiotic called rifampin to destroy the Hib bacteria they might be carrying and to prevent getting or spreading Hib. A health-care provider or the local health department can provide advice.

This fact sheet is for information only and is not meant to be used for self-diagnosis or as a substitute for consultation with a health-care provider. If you have questions about the disease described above, consult a health-care provider.

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