Influenza-Associated Hospitalizations During a High Severity Season - Influenza Hospitalization Surveillance Network, United States, 2024-25 Influenza Season.
Alissa O'Halloran,Jennifer Whitmill Habeck,Matthew Gilmer,Ryan Threlkel,Shua J Chai,Brenna Hall,Isaac Armistead,Nisha B Alden,James Meek,Kimberly Yousey-Hindes,Kyle P Openo,Lucy S Witt,Maya L Monroe,Patricia A Ryan,Lauren Leegwater,Sue Kim,Melissa McMahon,Ruth Lynfield,Khalil Harbi,Murtada Khalifa,Caroline McCahon,Grant Barney,Bridget J Anderson,Christina B Felsen,Brenda L Tesini,Nancy E Moran,Denise Ingabire-Smith,Melissa Sutton,M Andraya Hendrick,William Schaffner,H Keipp Talbot,Andrea George,Hafsa Zahid,Shikha Garg,Catherine H Bozio
{"title":"Influenza-Associated Hospitalizations During a High Severity Season - Influenza Hospitalization Surveillance Network, United States, 2024-25 Influenza Season.","authors":"Alissa O'Halloran,Jennifer Whitmill Habeck,Matthew Gilmer,Ryan Threlkel,Shua J Chai,Brenna Hall,Isaac Armistead,Nisha B Alden,James Meek,Kimberly Yousey-Hindes,Kyle P Openo,Lucy S Witt,Maya L Monroe,Patricia A Ryan,Lauren Leegwater,Sue Kim,Melissa McMahon,Ruth Lynfield,Khalil Harbi,Murtada Khalifa,Caroline McCahon,Grant Barney,Bridget J Anderson,Christina B Felsen,Brenda L Tesini,Nancy E Moran,Denise Ingabire-Smith,Melissa Sutton,M Andraya Hendrick,William Schaffner,H Keipp Talbot,Andrea George,Hafsa Zahid,Shikha Garg,Catherine H Bozio","doi":"10.15585/mmwr.mm7434a1","DOIUrl":null,"url":null,"abstract":"The U.S. 2024-25 influenza season was a high-severity season characterized by co-circulation of influenza A(H1N1)pdm09 and A(H3N2) viruses. Data from the Influenza Hospitalization Surveillance Network covering 9% of the U.S. population, were analyzed to compare laboratory-confirmed influenza-associated hospitalization rates and patient clinical characteristics from the 2024-25 season with data from past seasons. Based on preliminary data from influenza-associated hospital admissions from October 1, 2024, through April 30, 2025, the cumulative influenza-associated hospitalization rate (127.1 influenza-associated hospitalizations per 100,000 population) had surpassed all end-of-season rates during the period beginning with the 2010-11 season. Cumulative 2024-25 season rates were highest among persons aged ≥75 years (598.8). Across age groups, hospitalization rates during the 2024-25 season were 1.8 to 2.8 times higher than median historical rates during the period beginning with the 2010-11 season. Among hospitalized patients, 32.4% had received an influenza vaccine, and 84.8% received antiviral treatment, though children and adolescents aged 5-17 years had the lowest proportion of antiviral receipt (61.6%). Similar to past seasons, most patients hospitalized with influenza during the 2024-25 season (89.1%) had one or more underlying medical conditions, 16.8% were admitted to an intensive care unit, 6.1% received invasive mechanical ventilation, and 3.0% died in hospital. Seasonal influenza viruses can cause severe disease, particularly among persons who are at higher risk for complications. CDC recommends that all persons aged ≥6 months who do not have contraindications receive an annual influenza vaccine and that all hospitalized patients with influenza receive timely antiviral treatment to reduce the risk for complications.","PeriodicalId":18931,"journal":{"name":"Morbidity and Mortality Weekly Report","volume":"35 1","pages":"529-537"},"PeriodicalIF":0.0000,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Morbidity and Mortality Weekly Report","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.15585/mmwr.mm7434a1","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The U.S. 2024-25 influenza season was a high-severity season characterized by co-circulation of influenza A(H1N1)pdm09 and A(H3N2) viruses. Data from the Influenza Hospitalization Surveillance Network covering 9% of the U.S. population, were analyzed to compare laboratory-confirmed influenza-associated hospitalization rates and patient clinical characteristics from the 2024-25 season with data from past seasons. Based on preliminary data from influenza-associated hospital admissions from October 1, 2024, through April 30, 2025, the cumulative influenza-associated hospitalization rate (127.1 influenza-associated hospitalizations per 100,000 population) had surpassed all end-of-season rates during the period beginning with the 2010-11 season. Cumulative 2024-25 season rates were highest among persons aged ≥75 years (598.8). Across age groups, hospitalization rates during the 2024-25 season were 1.8 to 2.8 times higher than median historical rates during the period beginning with the 2010-11 season. Among hospitalized patients, 32.4% had received an influenza vaccine, and 84.8% received antiviral treatment, though children and adolescents aged 5-17 years had the lowest proportion of antiviral receipt (61.6%). Similar to past seasons, most patients hospitalized with influenza during the 2024-25 season (89.1%) had one or more underlying medical conditions, 16.8% were admitted to an intensive care unit, 6.1% received invasive mechanical ventilation, and 3.0% died in hospital. Seasonal influenza viruses can cause severe disease, particularly among persons who are at higher risk for complications. CDC recommends that all persons aged ≥6 months who do not have contraindications receive an annual influenza vaccine and that all hospitalized patients with influenza receive timely antiviral treatment to reduce the risk for complications.