Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

Haemophilus influenzae is a type of bacteria that mainly causes illness in babies and young children. These bacteria can cause infections in people of all ages ranging from mild, such as an ear infection, to severe, such as a bloodstream infection. In spite of the name, H. influenzae do not cause influenza (the “flu”). There are six identifiable types of H. influenzae bacteria (a through f) and other non-identifiable types (called nontypeable). The one people are most familiar with is H. influenzae type b, or Hib, that can be prevented with a vaccine. However, the vaccine does not protect against other types of the bacteria.