Fig. 5.

Adjusted odds ratios for complicated hospitalization in influenza-positive patients. Adjusted odds ratios for complicated hospitalization were determined in influenza-positive patients aged < 15 years (N = 1309), 15 to < 65 years (N = 1193), and ≥ 65 years (N = 776) by mixed effects logistic regression adjusted for age and vaccination for influenza during the previous 12 months and with site as a random effect. Complicated hospitalization was defined as ICU admission, mechanical ventilation, or death. Abbreviations: COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease