Table 2

Hazard ratios for individual predictors of influenza household transmission, adjusted on a daily score for exposure to influenza infection, the number of children under 15 years old and the number of adults in the household.

Individual predictor	Hazard ratio (95% CI)	P-value
Household contact
Age
>15 years	1
6–15 years	1.12 (0.73 to 1.71)	0.60
0–5 years	1.85 (1.09 to 3.26)	0.02
Influenza-like illness	1.54 (0.89 to 2.64)	0.12
Influenza vaccination	0.83 (0.40 to 1.70)	0.61
Chronic diseases	1.31 (0.72 to 2.36)	0.38
Current smoker	1.20 (0.93 to 1.55)	0.15
Index patient
Age
>15 years	1
6–15 years	1.68 (1.07 to 2.65)	0.02
0–5 years	1.93 (1.09 to 3.42)	0.02
Severity of disease on day 1 (≥ median^a)	1.35 (0.91 to 1.99)	0.13
Duration of disease (≥ median^b)	1.40 (0.96 to 2.03)	0.08

↵^aThe median severity of disease on day 0 (proportion of 13 clinical symptoms reported on the day of the visit to the general practitioner) was 0.65 for index cases (range = 0–1).
↵^bThe median duration of disease was 8 days in index cases (range = 0–15). CI = confidence interval.