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2025 theme: Vaccines

Abstract

Influenza A(H3N2) subclade K (J.2.4.1) has dominated the 2025/26 season start in England. Post-infection ferret antisera raised against northern hemisphere 2025/26 vaccine strains showed reduced reactivity to subclade K viruses in England, aligning with World Health Organization reports. Nevertheless, early post-vaccination, vaccine effectiveness against influenza-related emergency department attendances and hospital admissions remained within typical ranges, at 72–75% in children and adolescents (< 18 years) and 32–39% in adults. Hence, vaccination remains effective against clinical disease caused by influenza A(H3N2) viruses.

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/content/10.2807/1560-7917.ES.2025.30.46.2500854
2025-11-20
2026-03-15
/content/10.2807/1560-7917.ES.2025.30.46.2500854
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Early influenza virus characterisation and vaccine effectiveness in England in autumn 2025, a period dominated by influenza A(H3N2) subclade K
<p class="citation"> <span>Citation style for this article:</span> <span class="meta-value authors"> <a href="/search?value1=Freja+CM+Kirsebom&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Kirsebom Freja CM</a>, <a href="/search?value1=Catherine+Thompson&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Thompson Catherine</a>, <a href="/search?value1=Tiina+Talts&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Talts Tiina</a>, <a href="/search?value1=Beatrix+Kele&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Kele Beatrix</a>, <a href="/search?value1=Heather+J+Whitaker&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Whitaker Heather J</a>, <a href="/search?value1=Nick+Andrews&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Andrews Nick</a>, <a href="/search?value1=Nurin+Abdul+Aziz&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Abdul Aziz Nurin</a>, <a href="/search?value1=Christopher+Rawlinson&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Rawlinson Christopher</a>, <a href="/search?value1=Rebecca+E+Green&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Green Rebecca E</a>, <a href="/search?value1=Catherine+Quinot&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Quinot Catherine</a>, <a href="/search?value1=Nicholas+Gardner&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Gardner Nicholas</a>, <a href="/search?value1=Elizabeth+Waller&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Waller Elizabeth</a>, <a href="/search?value1=Alex+Allen&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Allen Alex</a>, <a href="/search?value1=Conall+H+Watson&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Watson Conall H</a>, <a href="/search?value1=Suzanna+LR+McDonald&option1=author&noRedirect=true" class="nonDisambigAuthorLink">McDonald Suzanna LR</a>, <a href="/search?value1=Maria+Zambon&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Zambon Maria</a>, <a href="/search?value1=Richard+Pebody&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Pebody Richard</a>, <a href="/search?value1=Mary+Ramsay&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Ramsay Mary</a>, <a href="/search?value1=Katja+Hoschler&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Hoschler Katja</a>, <a href="/search?value1=Anika+Singanayagam&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Singanayagam Anika</a>, <a href="/search?value1=Jamie+Lopez+Bernal&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Lopez Bernal Jamie</a></span>. Early influenza virus characterisation and vaccine effectiveness in England in autumn 2025, a period dominated by influenza A(H3N2) subclade K. <a href="/content/ecdc">Euro Surveill.</a> 2025;30(46):pii=2500854. <a href="https://doi.org/10.2807/1560-7917.ES.2025.30.46.2500854" title="doi link" target="_blank">https://doi.org/10.2807/1560-7917.ES.2025.30.46.2500854</a> <span class="ES_Article_citation"> <span class="generated">Received</span>: 11 Nov 2025;&nbsp;&nbsp; <span class="generated">Accepted</span>: 20 Nov 2025 </span> </p>
/content/10.2807/1560-7917.ES.2025.30.46.2500854
/content/10.2807/1560-7917.ES.2025.30.46.2500854
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