Prevalence and causes of seasonal influenza vaccination among children population in Hong Kong

Abstract

Background: Influenza is a typical infectious disease in Hong Kong, especially among the child population. There are two peaks of seasonal influenza every year. Hong Kong is located at the hypothetical epidemic hub of influenza pandemics, acting as a pioneering position in Asia. Though the population is paying more attention to the threat of influenza A H5N1 virus, the epidemics of influenza at every seasonal peak has been regarded as clinically insignificant in most Asian cities, especially in Hong Kong. The impacts on the child population are apparent. The flu outbreak in early 2015 has an unusual high death toll. Vaccination is a top prevention against such an infectious disease.

Objectives: This study attempted to identify the prevalence of seasonal influenza vaccination and the causes contributing to the outcomes.

Methods: This is a cross-sectional study. This study was conducted during the major flu season in Hong Kong with the baseline data collected from early March to early April 2015. 1002 parents or guardians of children aged under 15 responded to a telephone survey.

Results: The prevalence of seasonal influenza vaccination among children aged below 15 years old in Hong Kong is low (442 / 1002, 44.1%). The prevalence of annual seasonal influenza vaccination is even lower (212 / 1002, 21.2%). In the aspect of children’s age, the age range of 6 months to 3 years is reference for the odds ratio among other children at different age range. The odds of population at the age range of 4 to 6 years and having taken seasonal influenza vaccination is 2.49 times greater than the odds of the one at the age range of 6 months – 3 years and having seasonal influenza vaccination, with 95% confidence interval 1.51 - 4.14. The odds of population at the age range of 4 to 6 years and having taken annual seasonal influenza vaccination is 0.20 times less than the odds of the one at the age range of 6 months – 3 years and having annual seasonal influenza vaccination, with 95% confidence interval 0.07 – 0.51.

Conclusion: There was a low prevalence of seasonal influenza vaccination among the population of children aged under 15 years in Hong Kong. There is a positive association of cognitive risk, perceived utility of vaccines and associated factors in the decision made by parents for children seasonal influenza vaccination. There are a number of factors affecting parents or guardians’ seasonal influenza vaccination intention for their children.