ArticleInternational journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases2025
Effectiveness of influenza vaccination in preventing confirmed influenza cases and hospitalizations in Northern Spain, 2023/24 season: A population-based test-negative case-control study.
Article in International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers.
What it found
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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.
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Who cites it
3 citing papers in PubMed.
- Influenza Vaccine Effectiveness During the 2023/2024 Season: A Test-Negative Case-Control Study Among Emergency Hospital Admissions With Respiratory Conditions in Northern Ireland.Influenza and other respiratory viruses · 2025Article
- Article
- Hospitalizations and In-Hospital Fatality Among Influenza Patients in the Pre-Pandemic and COVID-19 Pandemic Periods.Journal of clinical medicine · 2025Article
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Authors and funding
12 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectiveWe estimated the influenza vaccination effectiveness (IVE) in preventing medical consultations and hospitalizations due to influenza during the 2023/24 season.
methodsTwo test-negative case-control studies analyzed patients who consulted primary healthcare or were hospitalized for respiratory symptoms and were tested for influenza by PCR in the 2023/24 season in Navarre, Spain. Influenza vaccination status in the current and previous seasons was compared between confirmed influenza cases and test-negative controls. IVE was calculated as (1-adjusted odds ratio)×100.
resultsOf 3133 hospitalized patients, 529 (17%) were positive for influenza: 71% A/H1N1, 23% A/H3N2, and 7% A nonsubtyped. IVE to prevent hospitalizations was 43% (95%CI: 26%, 56%) overall, 61% (95%CI: 32%, 77%) in people younger than 65 years old and 35% (95%CI: 10%, 53%) in older people. IVE was 48% (95%CI: 30%, 61%) against influenza A/H1N1, and 15% (95%CI: -42%, 49%) against influenza A/H3N2. IVE in people vaccinated only in the previous season was 28% (95%CI: -5%, 51%). Among 417 outpatients, 146 (35%) were confirmed for influenza. IVE to prevent outpatient cases was 49% (95%CI: -9%, 76%) overall and 42% (95%CI: -33%, 74%) against influenza A/H1N1.
conclusionsIVE was moderate against influenza A/H1N1 and low against influenza A/H3N2 in the 2023/24 season.
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Registered trials
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