Please cite this paper as: Higa et al. (2012) Role of neuraminidase inhibitor chemoprophylaxis in controlling nosocomial influenza: an observational study. Influenza and Other Respiratory Viruses 6(4), 299–303. Background  An influenza outbreak might result in disruption of services at acute care setting hospitals. Objectives  In this study, we retrospectively evaluated the use of neuraminidase inhibitor chemoprophylaxis for prevention of nosocomial spread of influenza in a university hospital. Patients/Methods  During the 3‐year study period, 202 index cases of influenza [30 hospitalized patients and 172 healthcare workers (HCW)] and 762 individuals who had had close contact with the index cases (248 hospitalized patients and 514 HCW) were identified. Of these contacts, 416 received neuraminidase inhibitor chemoprophylaxis. Results  When both the index cases and the close contacts were hospitalized patients, the incidence of influenza was lower among the close contacts who received chemoprophylaxis than among those who did not (odds ratio, 0·07; confidence interval, 0·01–0·49; P = 0·012). In contrast, when the index cases were HCW, the incidence of influenza was not different between close contacts who did or did not receive chemoprophylaxis. Conclusions  This study suggests that chemoprophylaxis might be useful to prevent nosocomial spread of infection between hospitalized patients.

Influenza virus infection in hospitals is a very important clinical issue. The objective of this study was to describe the effect of oseltamivir in controlling a nosocomial influenza virus infection with an observational study and case report. Intervention was carried out in a ward of the University of the Ryukyus Hospital. Symptomatic staff members were sent home for one week, and the infected inpatients were isolated. In addition, in an episode of influenza infection among the staff members and inpatients, oseltamivir (75 mg once a day for 7 days) was administered to all staff members as well as inpatients who had had close contact with the influenza patients. In the hospital ward, eight staff members (nurses and doctors) and ten hospitalized patients were definitively diagnosed with influenza A viral infection based on results of a rapid diagnostic test. Although a relatively large number of the staff members and inpatients had an influenza virus infection, it was possible that the use of oseltamivir efficiently minimized a nosocomial outbreak. It was very difficult to diagnose influenza A virus infection based on clinical symptoms. It was possible to minimize and end the outbreak immediately by using oseltamivir prophylaxis. With a review of the literature, it is considered that prophylaxis with anti‐influenza drugs are highly recommended in hospital settings.