Evidence map›Paper›PMID 42276011›Full record

ArticleEBioMedicine2026

Assessment of human immunity to A/H3N2 influenza subclade K during 2025 emergence.

Ruth Harvey, Ceilidh Welsh, Alexander Mp Byrne, David Greenwood, Phoebe Stevenson-Leggett, Monica Galiano, Dalan Bailey, Yung-Wai Chan, Jacob Boateng, Hannah Wolmuth-Gordon and 20 more

Abstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in EBioMedicine, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

  1. Article
  2. Loss of hemagglutination ability by H3N2 influenza A virus, subclade K.bioRxiv : the preprint server for biology · 2026
    Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

30 authors.

Ruth HarveyWorldwide Influenza Centre, Francis Crick Institute, London, UK.
Ceilidh WelshFrancis Crick Institute, London, UK.
Alexander Mp ByrneWorldwide Influenza Centre, Francis Crick Institute, London, UK.
David GreenwoodFrancis Crick Institute, London, UK.
Phoebe Stevenson-LeggettViral & Immune Surveillance Platform, Francis Crick Institute, UK.
Monica GalianoWorldwide Influenza Centre, Francis Crick Institute, London, UK.
Dalan BaileyThe Pirbright Institute, Ash Road, Pirbright, UK.
Yung-Wai ChanImmunisation and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK.
Jacob BoatengImmunisation and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK.
Hannah Wolmuth-GordonImmunisation and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK.
Heather WhitakerStatistics, Modelling and Economics Department, UK Health Security Agency, London, UK.
Kevin E BrownImmunisation and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK.
Anna Jeffery-SmithImmunisation and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK.
Alex AllenImmunisation and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK.
Gayatri AmirthanlingamImmunisation and Vaccine Preventable Diseases Division, UK Health Security Agency, London, UK.
Even FossumNational influenza Centre, Oslo, Norway; Division of Infection Control, Department of Virology, Norwegian Institute of Public Health, Oslo, Norway.
Elisabeth Lea VikseNational influenza Centre, Oslo, Norway; Division of Infection Control, Department of Virology, Norwegian Institute of Public Health, Oslo, Norway.
Andreas RohringerNational influenza Centre, Oslo, Norway; Division of Infection Control, Department of Virology, Norwegian Institute of Public Health, Oslo, Norway.
Olav HungnesNational influenza Centre, Oslo, Norway; Division of Infection Control, Department of Virology, Norwegian Institute of Public Health, Oslo, Norway.
Karoline BragstadNational influenza Centre, Oslo, Norway; Division of Infection Control, Department of Virology, Norwegian Institute of Public Health, Oslo, Norway.
Charles SwantonFrancis Crick Institute, London, UK; University College London, UK.
Bryan WilliamsUniversity College London, UK; National Institute for Health Research Biomedical Research Centre, University College London Hospitals, London, UK.
Sonia GandhiFrancis Crick Institute, London, UK; University College London, UK.
Steve GamblinFrancis Crick Institute, London, UK.
Edward J CarrFrancis Crick Institute, London, UK; UCL Centre for Renal and Bladder Health, University College London, UK.
Nicola S LewisWorldwide Influenza Centre, Francis Crick Institute, London, UK; Royal Veterinary College, Royal College Street, London, UK.
Emma C WallFrancis Crick Institute, London, UK; National Institute for Health Research Biomedical Research Centre, University College London Hospitals, London, UK; Centre for Infection and Immunobiology, Blizard Institute, Queen Mary University of London, UK. Electronic address: emma.wall@crick.ac.uk.
Mary Y WuViral & Immune Surveillance Platform, Francis Crick Institute, UK. Electronic address: mary.wu@crick.ac.uk.
Crick Serology Pipeline
Legacy Investigators

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundSeasonal influenza causes significant morbidity and mortality annually. In 2025, the genetically divergent A/H3N2 K subclade (J.2.4.1) emerged with substantial haemagglutinin mutations. However, despite suggested antigenic escape, UK vaccine effectiveness estimates and epidemiological data demonstrated a relatively normal influenza season across 2025-26. We examined neutralising antibody responses in human cohorts to investigate existing and vaccine-induced immunity to K clade viruses.

methodsWe characterised the antigenic relationships of a selection of A/H3N2 viruses spanning recent evolution including a subclade K virus using antigenic cartography, followed by serological antibody profiling of four human cohorts from the United Kingdom and Norway using microneutralisation (MN) and haemagglutination inhibition (HAI) assays.

findingsAntigenic cartography from single-infection ferret antisera suggests significant antigenic drift from the vaccine strains. MN and HAI titres from 243 individuals across 4 human cohorts (ages 1-105 years) were measured for comparison. The 2025/26 Northern Hemisphere seasonal inactivated egg-derived trivalent influenza vaccine (eTIV, with J.2 A/H3N2) significantly boosted MN and HAI titres against all A/H3N2 viruses tested, including a subclade K virus (p < 0.001). Furthermore, serological profiles of cohorts stratified by age groups (≤5, >5-≤15, >20-≤25, >25-<60, and ≥60) showed pre-existing reactivity against the emergent subclade K viruses, with minimal inter-age variation, suggesting there was not an immunity gap within particular age groups.

interpretationThe 2025/26 seasonal inactivated eTIV vaccine effectively boosted neutralising titres despite substantial genetic and antigenic drift. Human serological profiling should be included in risk assessments and continued surveillance.

fundingThe Francis Crick Institute with core funding from Cancer Research UK, UK Medical Research Council, and Wellcome Trust; UK Research and Innovation and UK Medical Research Council; National Institute for Health Research University College London Hospitals Biomedical Research Centre; UK Health Security Agency; Norwegian Institute of Public Health.

Indexed as

Influenza A Virus, H3N2 SubtypeInfluenza, HumanAdolescentAdultAgedAged, 80 and overAnimalsAntibodies, NeutralizingAntibodies, ViralAntigens, ViralChildChild, PreschoolFemaleHemagglutination Inhibition TestsHemagglutinin Glycoproteins, Influenza VirusHumansAntibodies, NeutralizingAntibodies, ViralAntigens, ViralHemagglutinin Glycoproteins, Influenza VirusInfluenza VaccinesAntigenic cartographyH3N2Haemagglutination inhibitionHuman serologyNeutralising antibodiesSeasonal influenzaSubclade KVaccine

Identifiers

PMID42276011
PMCPMC13276524

What OpenQuestion holds

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.