Table 3.

Logistic regression model of predictors of seropositivity

Risk factors	Odds ratio (95% CI) for seropositivity	P-value
Recalled having influenza that winter	1.9 (1.3 to 2.8)	0.0005
Had a seasonal influenza vaccine	2.0 (1.2 to 3.3)	0.0080
Age group, years
≤45	1.4 (1.0 to 1.9)	0.0290
>45	Reference