Lessons from a Nursing Home Outbreak of Influenza A

Abstract

OBJECTIVE: To characterize risk factors for outbreak-associated influenza illness and death in a nursing home. DESIGN: Outbreak investigation with predetermined and concurrently determined risk information. SETTING: A nursing home service in a multiward chronic care hospital, Honolulu, Oahu, 1989 to 1990. PATIENTS: Elderly nursing home patients receiving long-term care. INTERVENTIONS: Influenza vaccination, amantadine administration, and infection control measures. RESULTS: Neither routine infection control measures nor vaccination prevented illness, complications, or death in a nursing home outbreak of influenza A. The 55% case-fatality rate resulted from severe pneumonia. Influenza transmission may have been mediated by staff via either contaminated hands or fomites. CONCLUSIONS: Data from this and other outbreaks suggest that recommendations for preventing nosocomial influenza in the nation's 1.5 million nursing home residents should be reconsidered.