Clinical and Molecular Epidemiology of Invasive Haemophilus influenzae Serotype a Infections in Utah Children.

Background: Following widespread use of the Haemophilus influenzae serotype b (Hib) vaccine, H. influenzae serotype a (Hia) has emerged as an important pathogen in children in some regions. We describe the clinical features and molecular epidemiology of invasive Hia disease in children in Utah over an 11-year period.