Influenza vaccination is an effective public health measure that reduces the risk of severe illness and mortality following influenza infection. In South Korea, however, recent influenza vaccination patterns contrast with the changing epidemiology of ...
Influenza vaccination is an effective public health measure that reduces the risk of severe illness and mortality following influenza infection. In South Korea, however, recent influenza vaccination patterns contrast with the changing epidemiology of influenza. For example, although the burden of influenza has increased since the COVID-19 pandemic, influenza vaccination coverage among adults aged <65 years has not rebounded and has remained at levels similar to those observed during the pandemic, compared with adults aged ≥65 years. Adults aged <65 years constitute most of the population and workforce, experience frequent interpersonal contact, and thus face higher risks of infection and transmission, while also imposing substantial social and economic burdens due to productivity loss. These patterns suggest that determinants of influenza vaccination may differ by age group.
This study examined age-specific factors associated with influenza vaccination among adults aged <65 years. Using data from the 2023 Korea National Health and Nutrition Examination Survey (KNHANES), we analyzed 1,898 adults aged <65 years. Guided by Andersen’s Behavioral Model of Health Services Use, determinants of influenza vaccination were assessed across three age groups (19–39, 40–49, and 50–64 years).
Influenza vaccination coverage increased significantly with age (p<.05). Among adults aged 19–39 years, the likelihood of influenza vaccination was higher among women
(OR=1.76), those with a college education or higher (OR=1.38), and those who had used healthcare services recently (OR=1.54). Conversely, being unmarried (OR=0.50), having inadequate health literacy (OR=0.62), not undergoing health screening(OR=0.52), and current smoking (OR=0.65) were associated with lower odds of vaccination. Among adults aged 40–49 years, women (OR=1.3), individuals with higher income (OR=1.32), those with high-risk chronic conditions (OR=1.96), and recent healthcare utilization (OR=1.56) were more likely to be vaccinated, whereas divorce (OR=0.38), unemployment (OR=0.60), inadequate health literacy (OR=0.4), no health screening (OR=0.60), current smoking (OR=0.57), and high-risk alcohol use (OR=0.53) were associated with decreased vaccination. Among adults aged 50–64 years, women(OR=1.51), those with elementary school education or less(OR=2.32) or middle school education (OR=2.27), and those with high-risk chronic conditions (OR=1.49) had higher odds of vaccination; in contrast, having a college education or higher(OR=0.65), perceiving one’s health as god (OR=0.68), not undergoing health screening (OR=0.47), current smoking(OR=0.72), and high-risk alcohol use (OR=0.71) were associated with lower odds of vaccination.
These findings indicate that improving influenza vaccination uptake among adults aged <65 years requires age-tailored strategies. For adults aged 19–39 years, who have
relatively limited healthcare contact and greater time and cost barriers, priority strategies include co-delivery with clinical visits and health screenings, workplace- and university-based group vaccination, mobile reservation systems, and financial support to enhance access and convenience. For adults aged 40–49 years, institutionalizing regular vaccination through organizational settings and formal linkage with health screenings is important, while supplemental approaches—such as extended vaccination hours and community-based group vaccination—may be needed for the self-employed and unemployed. For adults aged 50–64 years, given increased healthcare utilization for chronic disease management, sustained recommendations in primary care, including standardized vaccination status checks and same-day vaccination or appointment scheduling, are warranted. Across all age groups, integrated strategies that link vaccination promotion with smoking cessation and alcohol reduction counseling should be considered.
This study is limited by reliance on secondary survey data (KNHANES), which restricts variable construction and interpretation. In addition, psychological and behavioral factors such as vaccination intention and prior vaccination history were unavailable, limiting explanations of age-group differences. Owing to the cross-sectional and self-reported nature of the data, causal inference and potential recall and social desirability biases cannot be excluded. Future research should incorporate additional relevant variables, link survey data with administrative sources such as immunization registry records, and employ longitudinal designs to more precisely examine determinants and pathways.