Haemophilus influenzae infections among hospitalized adult patients

Background: Relatively few data are available about Haemophilus influenzae (Hi) infection among adults Materials and Methods: We studied all adult patients with Hi infection hospitalized between 1988 and 1997 at the University Hospital of Berne. Data were abstracted retrospectively from clinical charts and microbiology records using a standardized questionnaire. Results: 12 invasive and 19 noninvasive Hi infections were observed during the study period. The main clinical manifestations were pneumonia (38.7%), bronchitis (29.0%) and meningitis (12.9%). Most patients (71.8%) had an underlying condition. Lethality was high (22.6%), especially in pneumonia patients (50%). The frequency of meningitis caused by Hi serotype b (Hib) seemed to decrease after 1990 when conjugated vaccines against Hib were introduced. Conclusion: Hi remains an important cause of lower respiratory and invasive disease associated with high lethality among polymorbid adult patients. The frequency of Hib infections may also decrease in adults due to herd immunity induced by universal vaccination of children.