ArticleClinical infectious diseases : an official publication of the Infectious Diseases Society of America2021
Effect of Antigenic Drift on Influenza Vaccine Effectiveness in the United States-2019-2020.
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 97 papers.
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Who cites it
97 citing papers in PubMed.
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- Immunogenicity and safety of the quadrivalent inactivated split-virion influenza vaccine in populations aged ≥ 3 years: A phase 3, randomized, double-blind, non-inferiority clinical trial.Human vaccines & immunotherapeutics · 2023Trial
- VirPLM: antigenic prediction of influenza A/H3N2 viruses with a fine-tuned protein language model.Bioinformatics (Oxford, England) · 2026Article
- NS1-Induced PARP1 Phase Transitions Prolongs Host Transcriptional Pausing to Promote Influenza A Virus Replication.Advanced science (Weinheim, Baden-Wurttemberg, Germany) · 2026Article
- Absolute and Relative Effectiveness of Cell Culture-Based and Egg-Based Quadrivalent Inactivated Influenza (Flu) Vaccine Products From the 2014-2015 to 2018-2019 Seasons, US Flu VE Network.Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · 2026Observational
- RELMα establishes a permissive environment for influenza virus infection through direct effects on lung epithelial cells.Journal of virology · 2026Article
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- Enhanced Immunogenicity and Cross-Neutralizing Activity of a Trivalent Adenoviral Vector-Based SARS-CoV-2 Vaccine in Mice.Journal of medical virology · 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
- Structural and temporal dynamics of pediatric influenza prevention and treatment: a comprehensive bibliometric analysis of historical evolution and emerging trends.Translational pediatrics · 2026Article
- Predicting the antigenic evolution of seasonal influenza viruses using phylogenetic convergence.bioRxiv : the preprint server for biology · 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
- Severity of Clinical Presentation and Outcomes in Hospitalized Adult People With Influenza by Type and Subtype, United States-2017-2020.Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · 2026Article
- Interim Estimates of 2025-26 Seasonal Influenza Vaccine Effectiveness - United States, September 2025-February 2026.MMWR. Morbidity and mortality weekly report · 2026Article
- AI-guided epitope engineering of a SARS-CoV-2 spike antigen for broad sarbecovirus neutralization.Frontiers in immunology · 2026Article
- Vaccination-driven evolution of infectious bronchitis virus in Korea: implication for the control of other coronavirus infections.Frontiers in veterinary science · 2026Review
- 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
- Article
- Pre-existing cross-reactive immunity to highly pathogenic avian influenza 2.3.4.4b A(H5N1) virus in the United States.Nature communications · 2025Article
- Replication in human cells supersedes serum antigenic match for the in vivo efficacy of an A/H1N1pdm09 LAIV virus.NPJ vaccines · 2025Article
37 more citing papers are in PubMed but not listed here.
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Authors and funding
19 authors.
Funding
Abstract
backgroundAt the start of the 2019-2020 influenza season, concern arose that circulating B/Victoria viruses of the globally emerging clade V1A.3 were antigenically drifted from the strain included in the vaccine. Intense B/Victoria activity was followed by circulation of genetically diverse A(H1N1)pdm09 viruses that were also antigenically drifted. We measured vaccine effectiveness (VE) in the United States against illness from these emerging viruses.
methodsWe enrolled outpatients aged ≥6 months with acute respiratory illness at 5 sites. Respiratory specimens were tested for influenza by reverse-transcriptase polymerase chain reaction (RT-PCR). Using the test-negative design, we determined influenza VE by virus subtype/lineage and genetic subclades by comparing odds of vaccination in influenza cases versus test-negative controls.
resultsAmong 8845 enrollees, 2722 (31%) tested positive for influenza, including 1209 (44%) for B/Victoria and 1405 (51%) for A(H1N1)pdm09. Effectiveness against any influenza illness was 39% (95% confidence interval [CI]: 32-44), 45% (95% CI: 37-52) against B/Victoria and 30% (95% CI: 21-39) against A(H1N1)pdm09-associated illness. Vaccination offered no protection against A(H1N1)pdm09 viruses with antigenically drifted clade 6B.1A 183P-5A+156K HA genes (VE 7%; 95% CI: -14 to 23%) which predominated after January.
conclusionsVaccination provided protection against influenza illness, mainly due to infections from B/Victoria viruses. Vaccine protection against illness from A(H1N1)pdm09 was lower than historically observed effectiveness of 40%-60%, due to late-season vaccine mismatch following emergence of antigenically drifted viruses. The effect of drift on vaccine protection is not easy to predict and, even in drifted years, significant protection can be observed.
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