{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"medRxiv"}],"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T09:08:36Z","timestamp":1785402516466,"version":"3.56.0"},"posted":{"date-parts":[[2026,7,27]]},"group-title":"Epidemiology","reference-count":21,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T00:00:00Z","timestamp":1785110400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/"}],"funder":[{"DOI":"10.13039\/100000030","name":"US Centers for Disease Control and Prevention","doi-asserted-by":"crossref","award":["5U01 IP001180-03"],"award-info":[{"award-number":["5U01 IP001180-03"]}],"id":[{"id":"10.13039\/100000030","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000030","name":"US Centers for Disease Control and Prevention","doi-asserted-by":"crossref","award":["5U01 IP001181-03"],"award-info":[{"award-number":["5U01 IP001181-03"]}],"id":[{"id":"10.13039\/100000030","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000030","name":"US Centers for Disease Control and Prevention","doi-asserted-by":"crossref","award":["5U01 IP001182-03"],"award-info":[{"award-number":["5U01 IP001182-03"]}],"id":[{"id":"10.13039\/100000030","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000030","name":"US Centers for Disease Control and Prevention","doi-asserted-by":"crossref","award":["5U01 IP001184-03"],"award-info":[{"award-number":["5U01 IP001184-03"]}],"id":[{"id":"10.13039\/100000030","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000030","name":"US Centers for Disease Control and Prevention","doi-asserted-by":"crossref","award":["5U01 IP001189-03"],"award-info":[{"award-number":["5U01 IP001189-03"]}],"id":[{"id":"10.13039\/100000030","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000030","name":"US Centers for Disease Control and Prevention","doi-asserted-by":"crossref","award":["5U01 IP001191-03"],"award-info":[{"award-number":["5U01 IP001191-03"]}],"id":[{"id":"10.13039\/100000030","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000030","name":"US Centers for Disease Control and Prevention","doi-asserted-by":"crossref","award":["5U01 IP001193-03"],"award-info":[{"award-number":["5U01 IP001193-03"]}],"id":[{"id":"10.13039\/100000030","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000030","name":"US Centers for Disease Control and Prevention","doi-asserted-by":"crossref","award":["5U01 IP001194-03"],"award-info":[{"award-number":["5U01 IP001194-03"]}],"id":[{"id":"10.13039\/100000030","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"crossref","award":["UL1TR001857"],"award-info":[{"award-number":["UL1TR001857"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,7,27]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                <jats:sec>\n                  <jats:title>Background<\/jats:title>\n                  <jats:p>Influenza vaccine effectiveness (VE) is assessed annually through prospective enrollment of patients presenting with acute respiratory symptoms in a test-negative study design. Influenza VE has also been estimated from electronic health record (EHR) databases by linking medical diagnoses, laboratory test results, and patient influenza vaccination. There are limited data on agreement between influenza VE estimates from prospective enrollment versus EHR databases.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Methods<\/jats:title>\n                  <jats:p>The US Influenza Vaccine Effectiveness Network prospectively enrolled outpatients meeting clinical screening criteria and collected respiratory specimens to determine influenza virus infection. Seven study sites also identified EHR databases that included diagnostic codes for outpatient encounters associated with medically attended acute respiratory illness (MAARI), clinical respiratory virus testing, and influenza vaccination status. Effectiveness of influenza vaccination against laboratory-confirmed influenza was estimated from both data sources using logistic regression models including patient age, study site, and month of illness as 100(%) x (1 \u2013 adjusted odds ratio), comparing influenza vaccination among laboratory-confirmed influenza-positive patients versus laboratory-confirmed influenza-negative patients.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>From October 2024\u2013April 2025, 2,016 (30%) of 6,793 prospectively enrolled patients and 75,885 (24%) of 282,444 EHR MAARI encounters had laboratory-confirmed influenza virus infection. Effectiveness of vaccination against laboratory-confirmed influenza was 36% (95% confidence interval [CI]: 26-44) among prospectively enrolled patients and 38% (95% CI: 36-39) among EHR MAARI encounters. Comparing influenza VE estimates from the two data sources, confidence intervals overlapped for all age groups except for adults aged \u226565 years: \u22123% (95% CI: \u221253\u201330) among prospective enrollment versus 35% (95% CI: 32\u201339) VE from EHR MAARI encounters.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Conclusion<\/jats:title>\n                  <jats:p>Overall, influenza VE estimates from retrospective EHR data were similar to VE estimates using the test-negative design with prospective enrollment. The age group-specific differences in estimated VE observed in US adults aged \u226565 years compared with younger age groups merit further investigation.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Key Points<\/jats:title>\n                  <jats:p>Retrospective EHR-based data and prospective enrollment of US patients using a test-negative design produced similar overall estimates of influenza VE during the 2024\u20132025 season.<\/jats:p>\n                <\/jats:sec>","DOI":"10.64898\/2026.07.23.26358258","type":"posted-content","created":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T16:55:26Z","timestamp":1785171326000},"source":"Crossref","is-referenced-by-count":0,"title":["Comparison of Influenza Vaccine Effectiveness Estimates Using Test-Negative Prospective Enrollment and Electronic Health Record Data, United States, 2024\u20132025"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1480-2843","authenticated-orcid":false,"given":"Ashley M.","family":"Price","sequence":"first","affiliation":[{"name":"Influenza Division, US Centers for Disease Control and Prevention, Atlanta, GA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Callie","family":"McLean","sequence":"additional","affiliation":[{"name":"Influenza Division, US Centers for Disease Control and Prevention, Atlanta, GA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Seana","family":"Cleary","sequence":"additional","affiliation":[{"name":"Influenza Division, US Centers for Disease Control and Prevention, Atlanta, GA, USA"},{"name":"STI Federal, Sault Tribe Incorporated, Sault Ste Marie, Michigan, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aleda M.","family":"Leis","sequence":"additional","affiliation":[{"name":"University of Michigan School of Public Health, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ivana A.","family":"Vaughn","sequence":"additional","affiliation":[{"name":"Henry Ford Health, Detroit, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stacey L.","family":"House","sequence":"additional","affiliation":[{"name":"Washington University School of Medicine in St. Louis, Department of Emergency Medicine, St. Louis, MO, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sam","family":"Ellsworth","sequence":"additional","affiliation":[{"name":"Washington University School of Medicine in St. Louis, Department of Emergency Medicine, St. Louis, MO, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Krissy Moehling","family":"Geffel","sequence":"additional","affiliation":[{"name":"University of Pittsburgh School of Medicine, Department of Family Medicine, Pittsburgh, PA, 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