Long-Term Epidemiological Trends of Human Adenovirus Infection in South Korea: A Single-Center Study (2007-2024).

Human adenoviruses (HAdVs; genus Mastadenovirus, family Adenoviridae) are major etiologic agents of respiratory infections, exerting a disproportionately large impact on children. However, no long-term study to date has spanned pre- and post-pandemic periods in a Korean tertiary setting. Here, we retrospectively analyzed 23,284 nasopharyngeal swabs collected between 2007 and 2024 at a tertiary medical center in South Korea. Most specimens were obtained from inpatients and outpatients presenting with fever or respiratory symptoms for differential viral diagnosis. HAdV was detected using real-time PCR, and positivity rates were compared by year, season, and age group. Overall, 2043 tested positive for HAdV. Annual positivity peaked in 2010, 2013, and 2016, followed by a sharp decline during the coronavirus disease 2019 pandemic, reaching its lowest level in 2024. Positivity was higher in summer and spring than in winter. Children aged 1-5 years had the highest positivity, whereas adults and older adults showed markedly lower rates. The disproportionate burden among children underscores the need for targeted surveillance, school-based infection control, and region-specific preparedness strategies. These findings provide crucial long-term evidence into adenovirus circulation in the post-pandemic era and provides an evidence-based foundation for future public health policy and infection control planning.