Table 2.

Factors associated independently with hospital-acquired influenza among patients in Edouard Herriot Hospital, Lyon (France), in influenza seasons 2004-05, 2005-06 and 2006-07

Characteristics	Adjusted ORa (95% CI)
Age, per 1 year older	1.03 (0.99-1.07)
Potential influenza source in the unitb	5.22 (1.08-25.22)
Proportion of vaccinated HCW in the unit
< 35%	1.0 (Ref.)
≥ 35%	0.07 (0.005-0.98)

OR, odds ratio; CI, confidence interval; HCW, healthcare workers.

^aMultivariate conditional logistic regression, adjusted on the other covariates

^bPotential sources of exposure to influenza (other patients or HCW) for 5 days before ILI or influenza occurrence in the same ward