A-277 Epidemic patterns of Influenza, Adenovirus, and RSV in Korea (2023-2024)

Abstract Background Strengthening surveillance systems for infectious diseases is crucial for preparing for epidemics and pandemics. Our objective is to establish a surveillance system for acute respiratory infections utilizing PCR test data from GC Labs, one of Korea’s largest independent clinical laboratories (ICLs). Additionally, we will compare the epidemic patterns of acute respiratory infections in 2023 and 2024 with data from the Korea Disease Control and Prevention Agency’s (KDCA) Respiratory Infections Sentinel Surveillance System. Methods GC Labs has developed a respiratory infection surveillance system that can automatically calculate the weekly PCR positive rates for 12 respiratory infections within its Laboratory Information System (LIS) and present this data on a dashboard. We analyzed the epidemic patterns for influenza, adenovirus, and respiratory syncytial virus (RSV) in 2023 and 2024. Additionally, we measured the correlation coefficients between GC Labs* weekly PCR positive rates and the weekly cases of Influenza-Like Illness (ILI), as well as for adenovirus and RSV, using weekly hospitalized cases from the Korea Disease Control Agency (KDCA). In 2025, we will incorporate data from Samkwang Medical Lab and EONE Laboratories. Results The influenza virus epidemic peaked in January 2023, with PCR positivity rates ranging from 10.9% to 25.5%. It re-emerged from mid-October to December, with rates between 12.5% and 24.6%. In 2024, the peak occurred again in January, with rates ranging from 11.1% to 19.8%, followed by a resurgence in December at approximately 10.0%. The adenovirus epidemic peaked between late July and mid-October 2023, with positivity rates ranging from 27.1% to 58.5%. In 2024, the rates remained below 10.0%. The RSV epidemic peaked between December 2023 and January 2024, reaching approximately 20.0%. It surged again in November and December, with rates ranging from 12.2% to 32.1%. Strong correlations with KDCA’s weekly Influenza-Like Illness (ILI) data were observed, with correlation coefficients of 0.95 (p < 0.0001) in 2023 and 0.96 (p < 0.0001) in 2024. For adenovirus, the correlations with the number of weekly hospitalized cases were 0.95 (p < 0.0001) in 2023 and 0.21 (p = 0.1332) in 2024. For Respiratory Syncytial Virus (RSV), the coefficients were 0.71 (p < 0.0001) in 2023 and 0.94 (p < 0.0001) in 2024. Conclusion The weekly PCR positive rates from the Laboratory Information System (LIS) at GC Labs demonstrate a strong correlation with the weekly number of Influenza-Like Illness (ILI) cases and hospitalizations reported by the Korea Disease Control and Prevention Agency’s (KDCA) Respiratory Infections Sentinel Surveillance System. This consistency underscores the importance of independent clinical laboratories in monitoring epidemics of acute respiratory infections. This research was conducted with the support of the Project for Advancing the Multi-Ministry Infectious Disease Prevention System, funded by the Korean government (Project ID: RS-2023-KH140570(HG23C1670))