Haemophilus influenzae is a bacterium that can cause a variety of serious diseases, including sepsis (bloodstream infection), meningitis (inflammation of the tissues that cover the brain and spinal cord), pneumonia, and epiglottis (inflammation of and swelling of the cartilage that covers the windpipe).
There are many different strains or types of Haemophilus influenzae, including type b (Hib). Before the Hib vaccine, this was the most common cause of life-threatening infections in children younger than 5 years of age.
Other types or strains (non-type b) of Haemophilus influenzae can cause invasive disease similar to Hib, but generally occur among the elderly or among people with weakened immune systems.
Additional Info Group
Last Revised: July 6, 2020
