Korea 2024-2025 Influenza and Respiratory Virus Laboratory Surveillance Report

This study characterizes the detection patterns of respiratory viruses and the virological characteristics of influenza viruses in the Republic of Korea from week 36 of 2024 to week 35 of 2025, thereby contributing to evidence-based infection control policies and strengthening public health responses.

Respiratory specimens were collected from patients with influenza-like illness at sentinel medical institutions and tested at 18 regional Institutes of Health and Environment. Molecular assays were conducted to detect respiratory viruses, and the distribution of etiologic agents was subsequently analyzed. The influenza viruses were further characterized through genetic, antigenic, and antiviral-resistance analyses to assess their similarity to the vaccine strains and susceptibility to antiviral agents.

Among specimens collected during the 2024-2025 season, influenza virus was the most frequently detected respiratory virus (15.2%), followed by rhinovirus (15.0%), severe acute respiratory syndrome coronavirus 2 (9.7%), parainfluenza virus (6.2%), adenovirus (4.9%), human metapneumovirus (4.8%), human coronavirus (4.7%), respiratory syncytial virus (3.6%), and human bocavirus (3.2%). The influenza virus subtypes included A(H1N1)pdm09 (39.6%), influenza B virus (36.8%), and A(H3N2) (23.6%). Circulating influenza viruses were genetically and antigenically similar to the 2024-2025 seasonal vaccine strains, and no antiviral-resistance mutations were detected.

The epidemiology of influenza and other respiratory viruses varies across seasons, underscoring the importance of continuous surveillance to inform infection control policies and strengthen public health preparedness. Through the Korea Respiratory Virus Integrated Surveillance System, our division will continue to monitor the circulation of respiratory viruses and the characteristics of influenza viruses and disseminate these findings on an ongoing basis.