Influenza Vaccine Effectiveness Against Medically Attended Outpatients Illness, United States, 2023-2024 Season.

Details

• Alternative Title:
  Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, 2025, v. 81, no. 4: Influenza Vaccine Effectiveness Against Medically Attended Outpatients Illness, United States, 2023-2024 Season.
• Journal Article:
  Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America
• Personal Author:
  Chung, Jessie R. ; Price, Ashley M. ; Zimmerman, Richard K. ; Moehling Geffel, Krissy ; House, Stacey L. ; Curley, Tara ; Wernli, Karen J. ; Phillips, C. Hallie ; Martin, Emily T. ; Vaughn, Ivana A. ; Murugan, Vel ; Scotch, Matthew ; Saade, Elie A. ; Faryar, Kiran A. ; Gaglani, Manjusha ; Ramm, Jason D. ; Williams, Olivia L. ; Walter, Emmanuel B. ; Kirby, Marie K. ; Keong, Lisa M. ; Kondor, Rebecca ; Ellington, Sascha R. ; Flannery, Brendan
• Corporate Authors:
  US Flu VE Network Investigators
• Description:
  The 2023-2024 US influenza season was characterized by a predominance of A(H1N1)pdm09 virus circulation with cocirculation of A(H3N2) and B/Victoria viruses. We estimated vaccine effectiveness (VE) in the United States against mild-to-moderate medically attended influenza illness in the 2023-2024 season.
  
  We enrolled outpatients aged ≥8 months with acute respiratory illness in 7 states. Respiratory specimens were tested for influenza type/subtype by reverse-transcriptase polymerase chain reaction. Influenza VE was estimated with a test-negative design comparing odds of testing positive for influenza among vaccinated versus unvaccinated participants. We estimated VE by virus subtype/lineage and A(H1N1)pdm09 genetic subclades.
  
  Among 6629 enrolled patients, 1780 (27%) tested positive for influenza, including 806 with A(H1N1)pdm09, 567 with B/Victoria, and 328 with A(H3N2). VE against any influenza illness was 44% (95% confidence interval, 36%-51%): 29% (15%-41%) against influenza A(H1N1)pdm09, 74% (65%-81%) against B/Victoria, and 30% (8%-47%) against A(H3N2). Statistically significant protection against any influenza was found for all age groups except adults aged 50-64 years. Lack of protection in this age group was specific to influenza A-associated illness. We observed differences in VE by birth cohort and A(H1N1)pdm09 virus genetic subclade.
  
  Vaccination reduced outpatient medically attended influenza overall by 44% and provided protection overall against circulating influenza A and B viruses. Serologic studies would help inform differences observed by age groups.
• Content Notes:
  Author manuscript
• Subjects:
  • Humans
  • Influenza, Human
  • Influenza Vaccines
  • Male
  • Female
  • Middle Aged
  • Adult
  • Outpatients
  • Adolescent
  • Influenza A Virus, H1N1 Subtype
  More +
• Keywords:
  • influenza
  • vaccine effectiveness
  • vaccination
  • test-negative design
  • case control
• Source:
  Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America, 2025, v. 81, no. 4
• DOI:
  https://doi.org/10.1093/cid/ciae658
• ISSN:
  1058-4838 ; 1537-6591
• Pubmed ID:
  39761230
• Pubmed Central ID:
  PMC12287938
• Document Type:
  Text
• Funding:
  U01 IP001182/IP/NCIRD CDC HHSUnited States/ ; UL1 TR001857/TR/NCATS NIH HHSUnited States/ ; U01 IP001180/IP/NCIRD CDC HHSUnited States/ ; U01 IP001191/IP/NCIRD CDC HHSUnited States/ ; U01 IP001193/IP/NCIRD CDC HHSUnited States/ ; 1U01 IP001182-01/US Centers for Disease Control and Prevention/ ; 1U01 IP001180-01/US Centers for Disease Control and Prevention/ ; U01 IP001181/IP/NCIRD CDC HHSUnited States/ ; 1U01 IP001194-01/US Centers for Disease Control and Prevention/ ; UL1TR001857/NH/NIH HHSUnited States/ ; U01 IP001189/IP/NCIRD CDC HHSUnited States/ ; U01 IP001184/IP/NCIRD CDC HHSUnited States/ ; 1U01 IP001181-01/US Centers for Disease Control and Prevention/ ; 1U01 IP001184-01/US Centers for Disease Control and Prevention/ ; 1U01 IP001191-01/US Centers for Disease Control and Prevention/ ; CC999999/ImCDC/Intramural CDC HHSUnited States/ ; 1U01 IP001193-01/US Centers for Disease Control and Prevention/ ; U01 IP001194/IP/NCIRD CDC HHSUnited States/ ; 1U01 IP001189-01/US Centers for Disease Control and Prevention/
• Genre:
  Journal Article
• Place as Subject:
  United States
• Pages in Document:
  e184-e191 (16 pdf pages)
• Volume:
  81
• Issue:
  4
• Download URL:
  https://stacks.cdc.gov/view/cdc/261799/cdc_261799_DS1.pdf
• File Type:
  [PDF - 241.48 KB]
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha-512:5da4443d4e72a1eb6304be1fd2f80cdc46ed5cda2a0ac5ed66995523b0d8d4ff5a3dd5cd066ef11608b0251bb387ad2a9ecc25ecde50993539b497ccd8a75724