Haemophilus influenzae disease

Haemophilus influenzae (Hi) disease is caused by a bacterial infection. The illness can range from mild to severe. Despite its name, Haemophilus influenzae has nothing to do with the influenza virus (flu).

Typically, Hi bacteria cause a mild infection. But severe infection can occur when the bacteria get into parts of the body where they are not usually found. This includes the bloodstream and brain. This type of infection causes invasive Haemophilus influenzae disease.

There are several types of Hi bacteria. Type b (known as Hib) can cause serious and life-threatening illness. Children under 5 are especially at risk.

The best way to prevent Hib disease is by getting a Hib vaccine. Before the vaccine, meningitis was the most common invasive disease caused by Hib. These cases have been reduced significantly because of immunization.