More about Haemophilus influenzae type b (Hib)

This page provides links to PATH's work on Haemophilus influenzae type b (Hib) and information about the disease and related vaccines.

Each year an estimated two to three million cases of Hib disease and more than 300,000 Hib deaths occur worldwide. The majority of Hib disease is in developing countries, and Hib’s victims are primarily children less than five years old.
Hib bacteria are a significant cause of childhood meningitis (inflammation of the covering of the brain) and bacterial pneumonia in children. Even though “influenza” is part of its name, Hib does not cause the “flu”. Hib can leave children with permanent neurological disabilities, including brain damage, hearing loss, and mental retardation. Most serious Hib disease occurs in children between 6 and 12 months old, and Hib can be more dangerous for children less than five years old. Children who have not been breastfed and those with underlying medical conditions, such as immune system deficiencies, are at greater risk for Hib disease.
Hib normally establishes itself in the nose or upper throat and is spread through sneezing, coughing, or speaking closely with an infected person. Children often carry Hib bacteria without showing any signs or symptoms (asymptomatic carriers), but they can still infect others.
Hib can be treated with the use of antibiotics; however, antibiotic resistance is a growing concern in the treatment of Hib in the developing world.

Several Hib conjugate vaccines have been licensed. All have shown protective efficacy in early infancy with virtually no side effects (except occasional, temporary redness or swelling at the injection site). Conjugate Hib vaccines are highly immunogenic, conferring more than 95 percent protection in infants receiving the complete series of pediatric vaccination (two to three doses starting after six weeks old). A booster shot is usually required at 12 to 18 months. To reduce the number of injections, Hib vaccine is sometimes given in combination with diphtheria-tetanus-pertussis vaccine.
Hib vaccines are routinely used in childhood immunization programs of many countries and territories, and since vaccine introduction, Hib disease has all but disappeared from most of these countries. However, Hib vaccines have not been used extensively in the developing world. When tested in several developing countries, including Chile, Indonesia, Uruguay, and the Gambia, the vaccine was proven to be as effective as in the United States. However, further disease burden and studies on vaccine effectiveness need to be undertaken, especially in Asia, Africa, and the Newly Independent States of Eastern Europe.
The WHO's Global Programme for Vaccines and Immunization recommends that the Hib vaccine be included in routine infant immunization programs.

There are several key causes of childhood pneumonia and meningitis (inflammation of the covering of the brain), including pneumococcus, Hib, and meningococcus bacteria. Learn more about pneumococcus. Learn more about meningococcus.

Page last updated: August 2008.