Morbidity and mortality associated with influenza exposure in long-term care facilities for dependent elderly people.

The purpose of this paper is to describe the impact of exposure to influenza on hospitalizations and deaths in the elderly residents of long-term care facilities (LTCFs). An observational, longitudinal, prospective, multicenter, cohort study collected influenza and influenza-like cases, diseases, hospitalizations, and deaths of dependent elderly residents of French LTCFs during the 2004-2005 seasonal influenza epidemic. A total of 8,041 residents of 98 participating LTCFs were included. The mean age was 85 +/- 9 years; 93% were vaccinated against influenza and 64% of the residents were exposed to influenza during the epidemic. Exposure to influenza increased both the all-cause risk of hospitalization (9.2% of the residents exposed vs. 7.4% of the residents not exposed) (relative risk, RR [95% confidence interval, CI] = 1.24 [1.05; 1.47]) and the all-cause risk of death (5.8% vs. 4.3%) (RR [95% CI] = 1.36 [1.10; 1.70]). Exposure to influenza increased the risks of death and hospitalization. Additional measures should be taken to avoid influenza exposure and apply recommendations more thoroughly in the particularly susceptible population of elderly LTCF residents.