ArticleClinical infectious diseases : an official publication of the Infectious Diseases Society of America2021
Influenza Vaccine Effectiveness for Prevention of Severe Influenza-Associated Illness Among Adults in the United States, 2019-2020: A Test-Negative Study.
Article in Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 22 papers, 2 of them syntheses that pooled it.
What it found
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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
22 citing papers in PubMed, 2 syntheses or guidelines pooled it, 30 citations in OpenAlex.
- Protection against influenza hospitalizations from enhanced influenza vaccines among older adults: A systematic review and network meta-analysis.Journal of the American Geriatrics Society · 2024Pooled it
- Does repeated influenza vaccination attenuate effectiveness? A systematic review and meta-analysis.The Lancet. Respiratory medicine · 2023Pooled it
- Elicitation of stem-directed antibodies in rhesus macaques by a conventional hemagglutinin immunogen.bioRxiv : the preprint server for biology · 2026Article
- Repeat Influenza Vaccination Effects in 2021/22 and 2022/23 in a Community-Based Cohort in Hong Kong.The Journal of infectious diseases · 2026Article
- Estimation of populations at risk for severe influenza and vaccination coverage in Mexico, 2010-2021.Frontiers in epidemiology · 2026Article
- Vaccine Effectiveness Against Influenza A(H1N1), A(H3N2), and B-Associated Hospitalizations, United States, 1 September 2023 to 31 May 2024.The Journal of infectious diseases · 2025Article
- COVID-19 and influenza vaccine Hesitancy among adults hospitalized in the United States, 2019-2022.Vaccine · 2025Article
- Advancing influenza vaccines: A review of next-generation candidates and their potential for global health impact.Vaccine · 2024Review
- Estimated Effectiveness of Influenza Vaccines in Preventing Secondary Infections in Households.JAMA network open · 2024Article
- Vaccine Effectiveness Against Influenza A-Associated Hospitalization, Organ Failure, and Death: United States, 2022-2023.Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · 2024Article
- Seasonal Influenza Vaccine Effectiveness in Persons Aged 15-64 Years: A Systematic Review and Meta-Analysis.Vaccines · 2023Review
- The burden of influenza and the role of influenza vaccination in adults aged 50-64 years: A summary of available evidence.Human vaccines & immunotherapeutics · 2023Review
- Vaccine Effectiveness Against Influenza-Associated Urgent Care, Emergency Department, and Hospital Encounters During the 2021-2022 Season, VISION Network.The Journal of infectious diseases · 2023Article
- The Impact of Coronavirus Disease 2019 on Viral, Bacterial, and Fungal Respiratory Infections.Clinics in chest medicine · 2023Review
- Influenza vaccine effectiveness in patients hospitalized with severe acute respiratory infection in Lithuania during the 2019-2020 influenza season: a test negative case - control study.Virology journal · 2023Article
- Ascertainment of vaccination status by self-report versus source documentation: Impact on measuring COVID-19 vaccine effectiveness.Influenza and other respiratory viruses · 2022Article
- Association of disease severity and death outcome with vaccination status of admitted COVID-19 patients in delta period of SARS-COV-2 in mixed variety of vaccine background.Saudi journal of biological sciences · 2022Article
- Disentangling the relative importance of T cell responses in COVID-19: leading actors or supporting cast?Nature reviews. Immunology · 2022Review
- Article
- Effectiveness of SARS-CoV-2 mRNA Vaccines for Preventing Covid-19 Hospitalizations in the United States.medRxiv : the preprint server for health sciences · 2021Article
Corrections and comments
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Authors and funding
27 authors at 13 institutions in 1 country.
Funding
Abstract
backgroundInfluenza vaccine effectiveness (VE) against a spectrum of severe disease, including critical illness and death, remains poorly characterized.
methodsWe conducted a test-negative study in an intensive care unit (ICU) network at 10 US hospitals to evaluate VE for preventing influenza-associated severe acute respiratory infection (SARI) during the 2019-2020 season, which was characterized by circulation of drifted A/H1N1 and B-lineage viruses. Cases were adults hospitalized in the ICU and a targeted number outside the ICU (to capture a spectrum of severity) with laboratory-confirmed, influenza-associated SARI. Test-negative controls were frequency-matched based on hospital, timing of admission, and care location (ICU vs non-ICU). Estimates were adjusted for age, comorbidities, and other confounders.
resultsAmong 638 patients, the median (interquartile) age was 57 (44-68) years; 286 (44.8%) patients were treated in the ICU and 42 (6.6%) died during hospitalization. Forty-five percent of cases and 61% of controls were vaccinated, which resulted in an overall VE of 32% (95% CI: 2-53%), including 28% (-9% to 52%) against influenza A and 52% (13-74%) against influenza B. VE was higher in adults 18-49 years old (62%; 95% CI: 27-81%) than those aged 50-64 years (20%; -48% to 57%) and ≥65 years old (-3%; 95% CI: -97% to 46%) (P = .0789 for interaction). VE was significantly higher against influenza-associated death (80%; 95% CI: 4-96%) than nonfatal influenza illness.
conclusionsDuring a season with drifted viruses, vaccination reduced severe influenza-associated illness among adults by 32%. VE was high among young adults.
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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.