Vaccine Effectiveness Against Influenza A(H1N1), A(H3N2), and B-Associated Hospitalizations, United States, 1 September 2023 to 31 May 2024.

Details

• Alternative Title:
  The Journal of Infectious Diseases, Oct-15-2025, v. 232, no. 4: Vaccine Effectiveness Against Influenza A(H1N1), A(H3N2), and B-Associated Hospitalizations, United States, 1 September 2023 to 31 May 2024.
• Journal Article:
  The Journal of Infectious Diseases
• Personal Author:
  Lewis, Nathaniel M. ; Harker, Elizabeth J. ; Cleary, Seana ; Zhu, Yuwei ; Grijalva, Carlos G. ; Chappell, James D. ; Rhoads, Jillian P. ; Baughman, Adrienne ; Casey, Jonathan D. ; Blair, Paul W. ; Jones, Ian D. ; Johnson, Cassandra A. ; Halasa, Natasha B. ; Lauring, Adam S. ; Martin, Emily T. ; Gaglani, Manju ; Ghamande, Shekhar ; Columbus, Cristie ; Steingrub, Jay S. ; Duggal, Abhijit ; Felzer, Jamie R. ; Prekker, Matthew E. ; Peltan, Ithan D. ; Brown, Samuel M. ; Hager, David N. ; Gong, Michelle N. ; Mohamed, Amira ; Exline, Matthew C. ; Khan, Akram ; Ferguson, Samantha A.N. ; Mosier, Jarrod ; Qadir, Nida ; Chang, Steven Y. ; Ginde, Adit A. ; Zepeski, Anne ; Mallow, Christopher ; Harris, Estelle S. ; Johnson, Nicholas J. ; Gibbs, Kevin W. ; Kwon, Jennie H. ; Vaughn, Ivana A. ; Ramesh, Mayur ; Safdar, Basmah ; Surie, Diya ; Dawood, Fatimah S. ; Ellington, Sascha ; Self, Wesley H.
• Description:
  The 2023-2024 influenza season included sustained elevated activity from December 2023 to February 2024 and continued activity through May 2024. Influenza A(H1N1), A(H3N2), and B viruses circulated during the season.
  
  During 1 September 2023 to 31 May 2024, a multistate sentinel surveillance network of 24 medical centers in 20 US states enrolled adults aged ≥18 years hospitalized with acute respiratory illness. 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 severe acute respiratory syndrome coronavirus 2 (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% confidence interval CI, 31%-48%) with varying estimates by age: 18-49 years, 53% (95% CI, 34%-67%); 50-64 years, 47% (95% CI, 31%-60%); ≥ 65 years, 31% (95% CI, 16%-43%). Protection was similar among immunocompetent patients (40%; 95% CI, 30%-49%) and immunocompromised patients (32%; 95% CI, 7%-50%). VE was statistically significant against influenza B (67%; 95% CI, 35%-84%) and A(H1N1) (36%; 95% CI, 21%-48%) and crossed the null against A(H3N2) (19%; 95% CI, -8% to 39%). VE was higher for patients 14-60 days from vaccination (54%; 95% CI, 40%-65%) than >120 days (18%; 95% CI, -1% to 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.
• Content Notes:
  Author manuscript
• Subjects:
  • Humans
  • Influenza, Human
  • Influenza A Virus, H1N1 Subtype
  • Influenza A Virus, H3N2 Subtype
  • Middle Aged
  • Hospitalization
  • Adult
  • Male
  • Female
  • Influenza Vaccines
  More +
• Keywords:
  • seasonal influenza
  • severe influenza
  • vaccine effectiveness
  • waning
  • hospitalization
• Source:
  The Journal of Infectious Diseases, Oct-15-2025, v. 232, no. 4
• DOI:
  https://doi.org/10.1093/infdis/jiaf185
• ISSN:
  0022-1899 ; 1537-6613
• Pubmed ID:
  40198276
• Pubmed Central ID:
  PMC13196694
• Document Type:
  Text
• Funding:
  R35 GM151147/GM/NIGMS NIH HHSUnited States/ ; K24 AI148459/AI/NIAID NIH HHSUnited States/ ; 75D30122C14944/IP/NCIRD CDC HHSUnited States/ ; 75D30122C12914/IP/NCIRD CDC HHSUnited States/ ; CC999999/ImCDC/Intramural CDC HHSUnited States/ ; CC/CDC HHSUnited States/
• Genre:
  Journal Article
• Place as Subject:
  United States
• Pages in Document:
  e626-e636 (19 pdf pages)
• Volume:
  232
• Issue:
  4
• Download URL:
  https://stacks.cdc.gov/view/cdc/261501/cdc_261501_DS1.pdf
• File Type:
  [PDF - 872.29 KB]
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha-512:e697ae08b8ccff31519f30add0599a6a6c59c0d29f4bc4387560346e102396f9f2f3229d5259f558e2b53f53681b97de8030b4d7604ef1b2c1e84c1f6b469f71