Interim Vaccine Effectiveness Against Influenza and Hospitalization, Republic of Korea, 2024–2025 (HIMM Network)
Year: 2025
Type: article
Study design: Observational Study
Abstract: Background: Influenza cases have surged earlier than usual during the 2024–2025 season, with A/H1N1 (pdm09) being the dominant strain. We aimed to investigate early estimates of influenza vaccine effectiveness (VE) for the 2024–2025 season to enhance our influenza response strategies. Methods: From November 1 to December 31, 2024, we enrolled 990 individuals with influenza-like illness from the hospital-based influenza surveillance network (Hospital-Based Influenza Morbidity and Mortality, HIMM), which consists of eight hospitals. Results: The overall adjusted VE was estimated to be −0.5% (95% confidence interval [CI], −34.0 to 24.6), with 0.4% (95% CI, −33.2 to 25.5) for influenza A. Analyses by influenza subtype were exploratory, given the limited number of subtyped cases. Although ineffective in preventing laboratory-confirmed influenza, influenza vaccination reduced influenza-related hospitalizations by 31.9% (95% CI, 3.5 to 51.9). Conclusions: It is necessary to enhance influenza vaccine effectiveness by selecting better-matched vaccine strains and introducing immune-enhanced vaccines.
Source: Vaccines
Institutions: Korea University, The Catholic University of Korea St. Vincent's Hospital, Catholic University of Korea, Hallym University, Inha University, Hallym University Kangnam Sacred Heart Hospital, Inha University Hospital, Chungbuk National University, Gachon University, Gachon University Gil Medical Center, Gachon University Medical Center
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,258
OpenAlex ID: W4415625762