{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T01:24:07Z","timestamp":1788917047559,"version":"build-2803163510"},"reference-count":36,"publisher":"Oxford University Press (OUP)","issue":"10","license":[{"start":{"date-parts":[[2025,9,17]],"date-time":"2025-09-17T00:00:00Z","timestamp":1758067200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"name":"Australian Sentinel Practices Research Network"},{"DOI":"10.13039\/501100003921","name":"Australian Government Department of Health and Aged Care","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100003921","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100009041","name":"National Department of Health","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100009041","id-type":"DOI","asserted-by":"publisher"}]},{"name":"National Institute for Communicable Diseases"},{"DOI":"10.13039\/100000030","name":"Centers for Disease Control and Prevention","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100000030","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Thailand Ministry of Public Health"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2025,9,29]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Routine monitoring of seasonal influenza vaccine effectiveness (VE) across multiple countries is essential to understand the performance of seasonal vaccine programs.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Using a test-negative study design, we estimated the effectiveness of the 2023 Southern Hemisphere formulation of the seasonal influenza vaccine in preventing outpatient medically attended influenza-like illness (ILI) in Australia, South Africa, and Thailand. Sentinel surveillance systems identified patients presenting with ILI who were tested by RT-PCR for influenza. VE was estimated as one minus the odds ratio comparing the vaccination status of test-positive cases and test-negative non-cases. Models adjusted for country, patients' age group, sex, underlying medical conditions, and calendar week of symptom onset. We assessed the duration of protection by modeling the effect of the interval between vaccination and symptom onset on influenza status.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>About 2469 ILI outpatients were identified, including 966 (39%) test-positive cases and 1503 (61%) test-negative non-cases; 78% (n = 750\/966) of viruses detected were influenza A; 8% (n = 72\/966) of test-positive cases and 29% (n = 439\/1503) of test-negative non-cases had received an influenza vaccine. Pooled VE was 68% (95% CI: 57%, 76%) against ILI with any influenza virus, 62% (95% CI: 39%, 76%) against influenza A(H1N1)pdm09, 60% (95% CI: 38%, 75%) against influenza A(H3N2), and 76% (95% CI: 59%, 86%) against influenza B. VE point estimates declined from 82% to 43% when the time from vaccination increased from 14 days to 150 days.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>The 2023 Southern Hemisphere formulation of seasonal influenza vaccines offered protection against ILI in three countries, underscoring the public health benefits of seasonal influenza vaccination programs.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/ofid\/ofaf560","type":"journal-article","created":{"date-parts":[[2025,9,6]],"date-time":"2025-09-06T11:49:38Z","timestamp":1757159378000},"source":"Crossref","is-referenced-by-count":1,"title":["Effectiveness of the 2023 Southern Hemisphere Influenza Vaccine Against Outpatient Influenza-Like Illness: A Multi-Country Test-Negative Design Study"],"prefix":"10.1093","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3879-6193","authenticated-orcid":false,"given":"Annette K","family":"Regan","sequence":"first","affiliation":[{"name":"Department of Research & Evaluation, Kaiser Permanente Southern California , Pasadena, California ,","place":["USA"]},{"name":"Department of Epidemiology, Fielding School of Public Health, University of California , Los Angeles, California ,","place":["USA"]},{"name":"School of Nursing and Health Professions, University of San Francisco , San Francisco, California ,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0702-5628","authenticated-orcid":false,"given":"Radhika","family":"Gharpure","sequence":"additional","affiliation":[{"name":"Influenza Division, Centers for Disease Control and Prevention , Atlanta, Georgia ,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6369-8483","authenticated-orcid":false,"given":"Monique","family":"Chilver","sequence":"additional","affiliation":[{"name":"The Discipline of General Practice, The University of Adelaide , Adelaide, South Australia ,","place":["Australia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nigel","family":"Stocks","sequence":"additional","affiliation":[{"name":"The Discipline of General Practice, The University of Adelaide , Adelaide, South Australia ,","place":["Australia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Siobhan","family":"St George","sequence":"additional","affiliation":[{"name":"Public Health and Surveillance Branch, Interim Australian Centre for Disease Control, Australian Government Department of Health, Disability and Ageing , Canberra, Australian Capital Territory ,","place":["Australia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7588-2480","authenticated-orcid":false,"given":"Sibongile","family":"Walaza","sequence":"additional","affiliation":[{"name":"Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases of the National Health Laboratory Service , Johannesburg ,","place":["South Africa"]},{"name":"School of Public Health, Faculty of Health Sciences, University of the Witwatersrand , Johannesburg ,","place":["South Africa"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0243-7455","authenticated-orcid":false,"given":"Anne","family":"von Gottberg","sequence":"additional","affiliation":[{"name":"Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases of the National Health Laboratory Service , Johannesburg ,","place":["South Africa"]},{"name":"School of Pathology, Faculty of Health Sciences, University of the Witwatersrand , Johannesburg ,","place":["South Africa"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9526-0133","authenticated-orcid":false,"given":"Nicole","family":"Wolter","sequence":"additional","affiliation":[{"name":"Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases of the National Health Laboratory Service , Johannesburg ,","place":["South Africa"]},{"name":"School of Pathology, Faculty of Health Sciences, University of the Witwatersrand , Johannesburg ,","place":["South Africa"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0376-2302","authenticated-orcid":false,"given":"Cheryl","family":"Cohen","sequence":"additional","affiliation":[{"name":"Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases of the National Health Laboratory Service , Johannesburg ,","place":["South Africa"]},{"name":"School of Public Health, Faculty of Health Sciences, University of the Witwatersrand , Johannesburg ,","place":["South Africa"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8355-8186","authenticated-orcid":false,"given":"Aaron M","family":"Samuels","sequence":"additional","affiliation":[{"name":"Influenza Division, Centers for Disease Control and Prevention , Atlanta, Georgia ,","place":["USA"]},{"name":"Influenza Program, Centers for Disease Control and Prevention , Pretoria ,","place":["South Africa"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kriengkrai","family":"Prasert","sequence":"additional","affiliation":[{"name":"Nakhon Phanom Provincial Hospital , Nai Mueang, Mueang Nakhon Phanom District, Nakhon Phanom ,","place":["Thailand"]},{"name":"Faculty of Public Health, Kasetsart University, Chalermprakiat Sakon Nakhon Province Campus , Mueang Sakon Nakhon District, Sakon 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