ArticleEuro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin2019
Paradoxical clade- and age-specific vaccine effectiveness during the 2018/19 influenza A(H3N2) epidemic in Canada: potential imprint-regulated effect of vaccine (I-REV).
Article in Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 49 papers, 2 of them syntheses that pooled 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.
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.
Who cites it
49 citing papers in PubMed, 2 syntheses or guidelines pooled it, 67 citations in OpenAlex.
- Does repeated influenza vaccination attenuate effectiveness? A systematic review and meta-analysis.The Lancet. Respiratory medicine · 2023Pooled it
- Relative Effectiveness of Cell-Cultured versus Egg-Based Seasonal Influenza Vaccines in Preventing Influenza-Related Outcomes in Subjects 18 Years Old or Older: A Systematic Review and Meta-Analysis.International journal of environmental research and public health · 2022Pooled it
- Induction of Cross-Reactive Hemagglutination Inhibiting Antibody and Polyfunctional CD4+ T-Cell Responses by a Recombinant Matrix-M-Adjuvanted Hemagglutinin Nanoparticle Influenza Vaccine.Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · 2021Trial
- The Influenza-Specific Immunoglobulin Repertoire - Nimble Yet Steeped in Tradition.Immunological reviews · 2026Review
- Interim 2025/26 influenza vaccine effectiveness estimates with immuno-epidemiological considerations for A(H3N2) subclade K protection, Canada, January 2026.Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin · 2026Article
- Low effectiveness of influenza vaccines vis-à-vis mechanism of protection by vaccines - potential causes and recommendations to improve control of influenza.Frontiers in immunology · 2026Review
- Emergence of seasonal influenza A(H3N2) variants with immune escape potential warrants enhanced molecular and epidemiological surveillance for the 2025-2026 season.Journal of the Association of Medical Microbiology and Infectious Disease Canada = Journal officiel de l'Association pour la microbiologie medicale et l'infectiologie Canada · 2025Article
- Influenza vaccine effectiveness in Europe and the birth cohort effect against influenza A(H1N1)pdm09: VEBIS primary care multicentre study, 2023/24.Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin · 2025Article
- Influenza and COVID-19 vaccination in Canadian blood donors: A comparison across pre- and post-pandemic periods.Vox sanguinis · 2025Article
- Early influenza virus exposure shapes the B cell response to influenza vaccination in individuals 50 years later.Immunity · 2025Article
- Immune imprinting: The persisting influence of the first antigenic encounter with rapidly evolving viruses.Human vaccines & immunotherapeutics · 2024Review
- Vaccination against rapidly evolving pathogens and the entanglements of memory.Nature immunology · 2024Review
- Article
- Immune imprinting in early life shapes cross-reactivity to influenza B virus haemagglutinin.Nature microbiology · 2024Article
- Article
- Population immunity of natural infection, primary-series vaccination, and booster vaccination in Qatar during the COVID-19 pandemic: an observational study.EClinicalMedicine · 2023Article
- Article
- Vaccine effectiveness estimates from an early-season influenza A(H3N2) epidemic, including unique genetic diversity with reassortment, Canada, 2022/23.Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin · 2023Article
- Antigenic Landscape Analysis of Individuals Vaccinated with a Universal Influenza Virus Vaccine Candidate Reveals Induction of Cross-Subtype Immunity.Journal of virology · 2023Article
- Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
16 authors at 9 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
IntroductionThe Canadian Sentinel Practitioner Surveillance Network reports vaccine effectiveness (VE) for the 2018/19 influenza A(H3N2) epidemic.AimTo explain a paradoxical signal of increased clade 3C.3a risk among 35-54-year-old vaccinees, we hypothesise childhood immunological imprinting and a cohort effect following the 1968 influenza A(H3N2) pandemic.MethodsWe assessed VE by test-negative design for influenza A(H3N2) overall and for co-circulating clades 3C.2a1b and 3C.3a. VE variation by age in 2018/19 was compared with amino acid variation in the haemagglutinin glycoprotein by year since 1968.ResultsInfluenza A(H3N2) VE was 17% (95% CI: -13 to 39) overall: 27% (95% CI: -7 to 50) for 3C.2a1b and -32% (95% CI: -119 to 21) for 3C.3a. Among 20-64-year-olds, VE was -7% (95% CI: -56 to 26): 6% (95% CI: -49 to 41) for 3C.2a1b and -96% (95% CI: -277 to -2) for 3C.3a. Clade 3C.3a VE showed a pronounced negative dip among 35-54-year-olds in whom the odds of medically attended illness were > 4-fold increased for vaccinated vs unvaccinated participants (p < 0.005). This age group was primed in childhood to influenza A(H3N2) viruses that for two decades following the 1968 pandemic bore a serine at haemagglutinin position 159, in common with contemporary 3C.3a viruses but mismatched to 3C.2a vaccine strains instead bearing tyrosine.DiscussionImprinting by the first childhood influenza infection is known to confer long-lasting immunity focused toward priming epitopes. Our findings suggest vaccine mismatch may negatively interact with imprinted immunity. The immunological mechanisms for imprint-regulated effect of vaccine (I-REV) warrant investigation.
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Registered trials
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.