Summary

Background: The incidence of invasive disease due to Haemophilus influenzae has decreased since the implementation of vaccination against serotype B.
Objectives: To describe the epidemiology, clinical and microbiological characteristics of patients with H. influenzae meningitis or bacteremia in the vaccine era in Israel.
Methods: We reviewed the medical records of all patients admitted to Shaare Zedek Medical Center between 1997 and 2010 who had blood or cerebrospinal fluid culture positive for H. influenzae.
Results: The study group comprised 104 patients – 57 children and 47 adults. Overall, 21 (20%) of the infections were due to serotype b. The children had shorter hospitalizations (6 vs. 12 days, P = 0.005) and lower mortality rate (5% vs. 28%, P = 0.003) as compared to the adults. Bacteremic pneumonia was the most common diagnosis in adults (45% vs. 28% in children, P = 0.08) while meningitis was more common in children (17% vs. 3.5%, P = 0.09). There was a seasonal pattern, with infections being more common during the winter and spring.
Conclusions: Invasive H. influenzae disease is uncommon but still exists in both children and adults. The disease course tends to be more severe in adults. Even in the global vaccination era, serotype b constitutes a significant portion of invasive disease.