ArticleVaccine2025
Assessment and mitigation of bias in influenza and COVID-19 vaccine effectiveness analyses - IVY Network, September 1, 2022-March 30, 2023.
Article in Vaccine, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 10 papers.
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Who cites it
10 citing papers in PubMed.
- Validity of influenza vaccine effectiveness calculations using a test-negative design in Thailand.American journal of epidemiology · 2026Article
- Influenza Vaccine Effectiveness Against Influenza-Associated Hospitalizations and Emergency Department or Urgent Care Encounters Among Children and Adults-VISION, United States, 2024-2025 Season.Open forum infectious diseases · 2026Article
- Influenza vaccine effectiveness against outpatient acute respiratory illness with laboratory-confirmed influenza, United States, 2024-25 season.Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · 2026Article
- Influenza vaccine effectiveness against influenza-associated hospitalizations and emergency department or urgent care encounters among children and adults - United States, 2024-25 season.medRxiv : the preprint server for health sciences · 2026Article
- Influenza vaccine effectiveness against outpatient acute respiratory illness with laboratory-confirmed influenza, United States, 2024-25 season.medRxiv : the preprint server for health sciences · 2026Article
- Estimated Effectiveness of 2024-2025 COVID-19 Vaccination Against Severe COVID-19.JAMA network open · 2026Article
- Does Home COVID-19 Testing Bias COVID-19 Vaccine Effectiveness Estimates?American journal of preventive medicine · 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
- Effectiveness of 2024-2025 COVID-19 Vaccination Against COVID-19 Hospitalization and Severe In-Hospital Outcomes - IVY Network, 26 Hospitals, September 1, 2024-April 30, 2025.medRxiv : the preprint server for health sciences · 2025Article
- Interim Estimates of 2024-2025 COVID-19 Vaccine Effectiveness Among Adults Aged ≥18 Years - VISION and IVY Networks, September 2024-January 2025.MMWR. Morbidity and mortality weekly report · 2025Article
Corrections and comments
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Authors and funding
48 authors.
Funding
Abstract
backgroundIn test-negative studies of vaccine effectiveness (VE), including patients with co-circulating, vaccine-preventable, respiratory pathogens in the control group for the pathogen of interest can introduce a downward bias on VE estimates.
methodsA multicenter sentinel surveillance network in the US prospectively enrolled adults hospitalized with acute respiratory illness from September 1, 2022-March 31, 2023. We evaluated bias in estimates of VE against influenza-associated and COVID-19-associated hospitalization based on: inclusion vs exclusion of patients with a co-circulating virus among VE controls; observance of VE against the co-circulating virus (rather than the virus of interest), unadjusted and adjusted for vaccination against the virus of interest; and observance of influenza or COVID-19 against a sham outcome of respiratory syncytial virus (RSV).
resultsOverall VE against influenza-associated hospitalizations was 6 percentage points lower when patients with COVID-19 were included in the control group, and overall VE against COVID-19-associated hospitalizations was 2 percentage points lower when patients with influenza were included in the control group. Analyses of VE against the co-circulating virus and against the sham outcome of RSV showed that downward bias was largely attributable the correlation of vaccination status across pathogens, but also potentially attributable to other sources of residual confounding in VE models.
conclusionExcluding cases of confounding respiratory pathogens from the control group in VE analysis for a pathogen of interest can reduce downward bias. This real-world analysis demonstrates that such exclusion is a helpful bias mitigation strategy, especially for measuring influenza VE, which included a high proportion of COVID-19 cases among controls.
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