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Volume 31, Number 6—June 2025

Dispatch

Investigation of Influenza A(H5N1) Virus Neutralization by Quadrivalent Seasonal Vaccines, United Kingdom, 2021–2024

Phoebe Stevenson-Leggett1, Lorin Adams1, David Greenwood1, Abi Lofts, Vincenzo Libri, Bryan Williams, Sonia Gandhi, Charles Swanton, Steve Gamblin, Edward J. Carr1, Ruth Harvey1, Nicola S. Lewis1, Mary Y. Wu, Emma C. Wall1Comments to Author , and Crick Neutralization Consortium2 and Legacy Investigators3
Author affiliation: The Francis Crick Institute, London, UK (P. Stevenson-Leggett, L. Adams, D. Greenwood, A. Lofts, S. Gandhi, C. Swanton, S. Gamblin, E.J. Carr, R. Harvey, N.S. Lewis, M.Y. Wu, E.C. Wall); Royal Veterinary College, London (L. Adams, N.S. Lewis); University College London Hospitals National Institute for Health Research Biomedical Research Unit, London (V. Libri, B. Williams, E.C. Wall); University College London, London (V. Libri, B. Williams, S. Gandhi, C. Swanton); University College London Centre for Kidney and Bladder Health, London (E.J. Carr); University College London Division of Infection and Immunity, London (E.C. Wall)

Main Article

Figure

Live-virus neutralization of preseasonal and postseasonal quadrivalent influenza vaccination in a study of influenza A(H5N1) virus neutralization by quadrivalent seasonal vaccines, United Kingdom, 2021–2024. Violin plots show paired serum samples before and after each seasonal vaccine (top row, 2023–24, n = 59; middle row, 2022–23, n = 54; bottom row, 2021–22, n = 30) tested against pandemic H1 and 2 highly pathogenic avian influenza H5 strains: H1N1 strain (A), H5N1 Cambodia strain (B), and H5H1 Texas dairy strain (C). Virus neutralization reported as log2-transformed IC50. Black diamonds indicate median IC50. Nonspecific cross-reactivity levels are shown as shaded areas. p values from McNemar tests are shown, comparing the number of persons above background (dashed line) before and after quadrivalent influenza vaccination by using a χ2 test. IC50, reciprocal titer at which 50% of viral infection is inhibited; NE, not estimated.

Figure. Live-virus neutralization of preseasonal and postseasonal quadrivalent influenza vaccination in a study of influenza A(H5N1) virus neutralization by quadrivalent seasonal vaccines, United Kingdom, 2021–2024. Violin plots show paired serum samples before and after each seasonal vaccine (top row, 2023–24, n = 59; middle row, 2022–23, n = 54; bottom row, 2021–22, n = 30) tested against pandemic H1 and 2 highly pathogenic avian influenza H5 strains: H1N1 strain (A), H5N1 Cambodia strain (B), and H5H1 Texas dairy strain (C). Virus neutralization reported as log2-transformed IC50. Black diamonds indicate median IC50. Nonspecific cross-reactivity levels are shown as shaded areas. p values from McNemar tests are shown, comparing the number of persons above background (dashed line) before and after quadrivalent influenza vaccination by using a χ2 test. IC50, reciprocal titer at which 50% of viral infection is inhibited; NE, not estimated.

Main Article

1These authors contributed equally to this article.

2Members of the Crick Neutralization Consortium are listed at the end of this article.

3Members of the Legacy Investigators are listed at the end of this article.

Page created: April 11, 2025
Page updated: May 14, 2025
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