Post-COVID-19 Resurgence of Human Adenovirus Type 3 Infection in Korean Children

We investigated the distribution of human adenovirus (HAdV) types and their associated clinical features during the post-coronavirus diseases 2019 period among Korean children. After their near absence in 2020-2021, HAdV-1 and HAdV-2 began circulating in early 2022, followed by a large HAdV-3-driven outbreak between June and September 2023. Children aged 2-5 years (43.0%) were the most affected, and 33.1% presented with lower respiratory tract infections, including pneumonia (25.4%). Overall, 12.4% of the patients required oxygen therapy, including 3.5% who required intensive care. These findings highlight the post-pandemic resurgence of HAdV infections in Korea, contributing to increased healthcare demands among children.