Changes in prevalence of influenza vaccination and strength of association of factors predicting influenza vaccination over time--results of two population-based surveys.

Two cross-sectional population-based telephone surveys interviewed 877 and 1,103 respondents aged >or=65. When compared to the first survey, respondents of the second survey were more likely to have heard of influenza vaccination (IV) (adjusted OR=4.09), to have received IV (adjusted OR=2.04) or to have done so in the last 6 months (adjusted OR=1.53), and to perceive IV as efficacious (adjusted OR=1.63). The strength of associations between predictors and IV outcomes differed in the two surveys; e.g., OR between perceived health impact and ever having received IV were, respectively, 1.11 (p>0.05) versus 1.91 (p<0.05). IV-related behaviors and perceptions therefore changed over time.