Prevalence and associated factors of seasonal influenza vaccination among 24- to 59-month-old children in Hong Kong

Background: Influenza results in severe complications among 24- to 59-month-old children, who are recommended by the WHO to take up influenza vaccination (IV) annually. Health promotion is warranted. Yet, there is a dearth of studies on IV prevalence and associated factors in this age group.

Methods: A random population-based telephone survey interviewed 540 parents of Chinese children aged 24-59 months in Hong Kong during March through June, 2011. Constructs of the Health Belief Model (HBM) and subjective norm formed basis for assessing parental perceptions on influenza and IV. For data analysis, adjusted, and stepwise multiple logistic regression models were fit.

Results: The prevalence of having taken up at least one dose and two doses of IV among children aged 24-59 months was 58.9 and 42.4%, respectively. Significant associated factors included family members' IV experience (ORu=5.37, 95% CI: 3.48, 8.29), variables related to the HBM constructs (except perceived severity) [perceived susceptibility of seasonal influenza (ORu=2.03, 95% CI: 1.39, 2.95), perceived benefits of IV (ORu=3.11, 95% CI: 2.05, 4.71), perceived barriers (ORu=0.49, 95% CI: 0.25, 0.96) of IV, and cue to action (ORu=4.79, 95% CI: 2.87, 7.99)], supportive subjective norm (ORu=4.26, 95% CI: 2.91, 6.25), and level of fear felt during the H1N1 pandemic (ORu=1.97, 95% CI: 1.01, 3.87). Adjusted for the child's age, the same significant factors were found. Exposure to related media messages was statistically non-significant.

Conclusion: The reported IV prevalence was higher than that of 24- to 59-month-old children reported in other studies. There is room for improvement through health promotion, which should modify parental cognitions related to HBM (except perceived severity and self-efficacy) and involve family members to create subjective norm. Media campaigns may be inadequate for promotion of IV; use of the setting approach may be considered.