Current Epidemiology and Trends in Invasive Haemophilus influenzae Disease—United States, 2009–2015

BACKGROUND. Following Haemophilus influenzae serotype b (Hib) conjugate vaccine introduction in the 1980s, Hib disease in young children dramatically decreased, and epidemiology of invasive H. influenzae changed. METHODS. Active surveillance for invasive H. influenzae disease was conducted through Active Bacterial Core surveillance sites. Incidence rates were directly standardized to the age and race distribution of the US population. RESULTS. During 2009–2015, the estimated mean annual incidence of invasive H. influenzae disease was 1.70 cases per 100 000 population. Incidence was highest among adults aged ≥65 years (6.30) and children aged