Haemophilus influenzae type b (Hib) can cause serious invasive illness such as meningitis, bacteremia, epiglottitis, and pneumonia. Hib infection is spread primarily by respiratory droplets (droplet spread) produced when an infected person coughs or sneezes. Prior to the introduction of Hib conjugate vaccine in 1987, Hib was the leading cause of bacterial meningitis (causing over 20,000 cases per year) and a major cause of other serious bacterial infections among children under five years of age in the United States. After 1987, Hib cases rapidly declined, and invasive disease from Hib infection is rare today. Non-typeable H. influenzae is rarely responsible for serious illness but is a common cause of ear infections in children. Invasive disease due to Haemophilus influenzae is only reportable in children less than five years of age because this is the age group at risk for severe disease.

Resources for the general public

• For parents: Is your child protected against Hib disease?, CDC
• Hib vaccine information statement, CDC
• Immunization Action Coalition questions and answers about Hib vaccine
• Vaccine Information You Need, Immunization Action Coalition

Resources for health care professionals

• Haemophilus influenzae is a reportable condition in King County: See disease reporting requirements.
• Hib technical information, CDC