Fig. 7

Adjusted coefficients for long hospital stays in influenza-positive patients. Coefficient estimates for length of hospital stay were determined in influenza-positive patients aged < 15 years (N = 1306), 15 to < 65 years (N = 1189), and ≥ 65 years (N = 775) by linear mixed-effects regression model adjusted for age and vaccination status and with site as a random effect. The coefficient indicates the change in length of hospital stay in days when the indicated factor is changed by one unit (i.e. from yes to no). Abbreviations: COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease