Journal article
Vaccine Effectiveness Against Influenza A(H1N1), A(H3N2), and B-Associated Hospitalizations-United States, September 1, 2023-May 31, 2024
The Journal of infectious diseases, Vol.232(4), pp.e626-e636
10/15/2025
DOI: 10.1093/infdis/jiaf185
PMCID: PMC13196694
PMID: 40198276
Abstract
The 2023-2024 influenza season included sustained elevated activity from December 2023-February 2024 and continued activity through May 2024. Influenza A(H1N1), A(H3N2), and B viruses circulated during the season.
During September 1, 2023-May 31, 2024, a multistate sentinel surveillance network of 24 medical centers in 20 U.S. states enrolled adults aged ≥18 years hospitalized with acute respiratory illness (ARI). Consistent with a test-negative design, cases tested positive for influenza viruses by molecular or antigen test, and controls tested negative for influenza viruses and SARS-CoV-2. Vaccine effectiveness (VE) against influenza-associated hospitalization was calculated as (1 - adjusted odds ratio for vaccination) × 100%.
Among 7690 patients, including 1170 influenza cases (33% vaccinated) and 6520 controls, VE was 40% (95% CI: 31%-48%) with varying estimates by age (18-49 years: 53% [34%-67%]; 50-64 years: 47% [31%-60%]; ≥65 years: 31% [16%-43%]). Protection was similar among immunocompetent patients (40% [30%-49%]) and immunocompromised patients (32% [7-50%]). VE was statistically significant against influenza B (67% [35%-84%]) and A(H1N1) (36% [21%-48%]) and crossed the null against A(H3N2) (19% [-8%-39%]). VE was higher for patients 14-60 days from vaccination (54% [40%-65%]) than >120 days (18% [-1%-33%]).
During 2023-2024, influenza vaccination reduced the risk of influenza A(H1N1)- and influenza B-associated hospitalizations among adults; effectiveness was lower in patients vaccinated >120 days prior to illness onset compared with those vaccinated 14-60 days prior.
Details
- Title: Subtitle
- Vaccine Effectiveness Against Influenza A(H1N1), A(H3N2), and B-Associated Hospitalizations-United States, September 1, 2023-May 31, 2024
- Creators
- Anne Zepeski - Carver College of Medicine, Iowa City, Iowa, USANathaniel M Lewis - Influenza Division, CDC, Atlanta Georgia, USAElizabeth J Harker - Influenza Division, CDC, Atlanta Georgia, USASeana Cleary - Influenza Division, CDC, Atlanta Georgia, USAYuwei Zhu - Vanderbilt University Medical CenterCarlos G Grijalva - Vanderbilt University Medical CenterJames D Chappell - Vanderbilt University Medical CenterJillian P Rhoads - Vanderbilt University Medical CenterAdrienne Baughman - Vanderbilt University Medical CenterJonathan D Casey - Vanderbilt University Medical CenterPaul W Blair - Vanderbilt University Medical CenterIan D Jones - Vanderbilt University Medical CenterCassandra A Johnson - Vanderbilt University Medical CenterNatasha B Halasa - Vanderbilt University Medical CenterAdam S Lauring - University of MichiganEmily T Martin - University of MichiganManju Gaglani - Baylor College of MedicineShekhar Ghamande - Baylor College of MedicineCristie Columbus - Texas A&M University College of Medicine, Dallas, Texas, USAJay S Steingrub - Baystate Medical CenterAbhijit Duggal - Cleveland ClinicJamie R Felzer - Emory UniversityMatthew E Prekker - Hennepin County Medical CenterIthan D PeltanSamuel M BrownDavid N Hager - Johns Hopkins University School of MedicineMichelle N Gong - Albert Einstein College of MedicineAmira Mohamed - Albert Einstein College of MedicineMatthew C Exline - The Ohio State UniversityAkram Khan - Oregon Health & Science UniversitySamantha A N Ferguson - Stanford University School of MedicineJarrod Mosier - University of ArizonaNida Qadir - Ronald Reagan UCLA Medical CenterSteven Y Chang - Ronald Reagan UCLA Medical CenterAdit A Ginde - University of Colorado School of Medicine, Aurora, Colorado, USAChristopher Mallow - University of MiamiEstelle S Harris - University of UtahNicholas J Johnson - University of WashingtonKevin W Gibbs - Wake Forest School of Medicine, Winston-Salem, North Carolina, USAJennie H Kwon - Washington University in St. LouisIvana A Vaughn - Henry Ford Health, Detroit, Michigan, USAMayur Ramesh - Ford Motor Company (United States)Basmah Safdar - Yale UniversityDiya Surie - Division of COVID-19 and Other Respiratory Viral Diseases, CDC, Atlanta, Georgia, USAFatimah S Dawood - Division of COVID-19 and Other Respiratory Viral Diseases, CDC, Atlanta, Georgia, USASascha Ellington - Influenza Division, CDC, Atlanta Georgia, USAWesley H Self - Vanderbilt University Medical Center
- Resource Type
- Journal article
- Publication Details
- The Journal of infectious diseases, Vol.232(4), pp.e626-e636
- DOI
- 10.1093/infdis/jiaf185
- PMID
- 40198276
- PMCID
- PMC13196694
- NLM abbreviation
- J Infect Dis
- ISSN
- 0022-1899
- eISSN
- 1537-6613
- Publisher
- OXFORD UNIV PRESS INC
- Grant note
- Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases: 75D30122C12914, 75D30122C14944
This work was supported by Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases (contract numbers 75D30122C12914 and 75D30122C14944 to W. H. S.).
- Language
- English
- Electronic publication date
- 04/08/2025
- Date published
- 10/15/2025
- Academic Unit
- Emergency Medicine; Pharmacy Practice and Science
- Record Identifier
- 9984808285402771
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