In 2020, along with COVID-19 outbreaks, a decline of influenza vaccination coverage in older adults was observed regardless of free immunizations. It is likely due to behavioral changes to reduce the risk of COVID-19 transmission. This is supported by a greater reduction of influenza vaccination coverage in regions with higher COVID-19 outbreaks, as well as by South Korea's high medical accessibility and highly congested medical facilities. To sustain a high level of vaccination coverage of high-risk population during epidemics, additional efforts beyond free vaccination policies should be implemented.
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