National trends in influenza vaccination rates in South Korea before and during the COVID-19 pandemic, 2011–2022

<p dir="ltr">Objective: Despite the global decrease in influenza infections during the coronavirus disease 2019 (COVID-19) pandemic, seasonal influenza remains a significant health issue. South Korea, known for its robust pandemic response and high influenza vaccination rates, offers a unique context for examining changes in vaccination trends during the pandemic. Using nationally representative data, we aimed to understand the impact of the pandemic on influenza vaccination behavior over a 12-year period and to identify vulnerable groups.</p><p dir="ltr">Methods: We analyzed influenza vaccination rates in South Korea between 2011–2022, focusing on pandemic-related impacts. The data of 2,426,139 adults (≥ 19 years) from the Korea Community Health Survey were used to assess demographic and sociological factors influencing vaccination behaviors.</p><p dir="ltr">Results: We observed an increase in influenza vaccination rates during the pre-COVID-19 period from 2011–2013 (weighted prevalence: 46.68% [95% confidence interval (<i>CI</i>): 46.55–46.82]) to 2017–2019 (weighted prevalence: 52.50% [<i>95% CI</i>: 52.38–52.63]). However, a significant decline was observed in 2022, the late-COVID-19 pandemic period (weighted prevalence: 55.78% [95% <i>CI</i>: 55.56–56.01]), compared with the mid-pandemic period in 2021 (weighted prevalence: 59.12% [<i>95% CI:</i> 58.91– 59.32]), particularly among populations traditionally prioritized for influenza vaccination, including older adults (≥ 65 years) and patients with chronic diseases and low educational and income levels.</p><p dir="ltr">Conclusion: The influenza vaccination rate in South Korea was significantly affected by the COVID-19 pandemic, showing a notable decrease among vulnerable demographic groups. This suggests the need for targeted public health strategies to address vaccine hesitancy and improve vaccination rates, particularly among high-risk populations.</p>