Trends and factors associated with influenza vaccination in subjects with asthma: analysis of the Korea National Health and Nutrition Examination Survey between 2010 and 2019

Background: Despite the importance of influenza vaccination, its rates in subjects with asthma are suboptimal, especially in the young population. Methods: Among 72,843 adults aged ⩾18 years from the Korea National Health and Nutrition Examination Survey conducted between 2010 and 2019, 1643 with asthma were included. The yearly trends and factors associated with influenza vaccination were analyzed in subjects with asthma. In addition, stratified analyses were performed by age group (<65 versus ⩾65 years). Results: During the study period, the overall influenza vaccination rate among subjects with asthma fluctuated from 51.0% to 64.3%, with a consistently higher vaccination rate in elderly subjects than in young subjects. Among young subjects with asthma, factors positively associated with influenza vaccination were female sex [adjusted odds ratio (aOR) = 1.66, 95% confidence interval (CI) = 1.11–2.49], current asthma being treated (aOR = 1.69, 95% CI = 1.14–2.50), history of pulmonary tuberculosis (aOR = 2.01, 95% CI = 1.04–3.87), and dyslipidemia (aOR = 1.86, 95% CI = 1.05–3.30). However, unmarried subjects showed an inverse relationship (aOR = 0.50, 95% CI = 0.34–0.75). In elderly subjects, unmarried status (aOR = 0.52, 95% CI = 0.29–0.94), being underweight (aOR = 0.29, 95% CI = 0.09–0.97), and having a low income (aOR = 0.42, 95% CI = 0.18–0.97) were factors negatively associated with influenza vaccination. Conclusion: In the last 10 years, influenza vaccination rates have still been insufficient in subjects with asthma, particularly in young subjects. Considering the factors that are influencing the vaccination rates of young subjects, public policies to increase influenza vaccination rates in subjects with asthma need to be established urgently.