{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T04:26:42Z","timestamp":1787632002555,"version":"build-2736575974"},"reference-count":21,"publisher":"Wiley","issue":"8","license":[{"start":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T00:00:00Z","timestamp":1785974400000},"content-version":"vor","delay-in-days":5,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,8,1]],"date-time":"2026-08-01T00:00:00Z","timestamp":1785542400000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/501100001626","name":"Public Health Agency","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100001626","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Influenza Resp Viruses"],"published-print":{"date-parts":[[2026,8]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Seasonal influenza causes substantial morbidity and hospitalisation each year. We estimated influenza vaccine effectiveness (VE) against laboratory\u2010confirmed influenza\u2010associated hospitalisation among patients in Northern Ireland (NI) during the 2024\/25 influenza season.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We used a test\u2010negative design to estimate VE against hospitalisation. Influenza\u2010positive cases and test\u2010negative controls were identified through the national laboratory surveillance system and linked to hospital admission and vaccination records. VE was estimated by influenza type\/subtype, age group, sex, vaccine type and time since vaccination.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Among 15,133 hospitalised patients, 2024 (13.4%) tested positive for influenza. Among the 2024 patients admitted with laboratory\u2010confirmed influenza, the vast majority tested positive for influenza A (\n                      <jats:italic>n<\/jats:italic>\n                      \u2009=\u20091803; 89.1%), whereas 221 cases (10.9%) were influenza B. Subtyping of influenza A identified 606 A(H1) infections and 93 A(H3) infections; the remaining 1104 influenza A samples were not subtyped. VE against laboratory\u2010confirmed influenza infection was 46.0% (95% CI: 39.7% to 51.8%), with higher VE in children aged 2\u201317\u2009years (60.8%; 95% CI: 48.3% to 70.5%) than in adults aged 18\u201364\u2009years (40.5%; 95% CI: 24.9% to 53.2%) and \u2265\u200965\u2009years (42.3%; 95% CI: 33.2% to 50.1%). VE against influenza A across all ages was 41.4% (95% CI: 34.2% to 47.9%). Vaccination reduced the odds of hospitalisation due to influenza A(H1) by 44.3% (95% CI: 33.2% to 53.7%) and A(H3) by 49.9% (95% CI: 20.3% to 69.3%). VE against influenza B was higher at 76.4% (95% CI: 64.9% to 84.7%). For influenza A, VE was highest 2\u20138\u2009weeks after vaccination at 51.9% (95% CI: 42.1% to 60.1%) and declined with time since vaccination to 44.6% (95% CI: 35.6% to 52.5%) at 9\u201316\u2009weeks and 41.4% (95% CI: 15.4% to 60.1%) at \u2265\u200916\u2009weeks. VE against influenza B remained high throughout the season. No statistically significant differences in VE by vaccine type were found.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Influenza vaccination reduced the risk of hospitalisation with laboratory\u2010confirmed influenza during the 2024\/25 season, offering meaningful protection at individual and population levels, with the greatest benefit observed in children.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1111\/irv.70303","type":"journal-article","created":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T12:26:04Z","timestamp":1786019164000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Effectiveness of Influenza Vaccines and Duration of Protection Against Hospitalisation During the 2024\/25 Season in Northern Ireland, UK"],"prefix":"10.1111","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8417-1602","authenticated-orcid":false,"given":"Magda","family":"Bucholc","sequence":"first","affiliation":[{"name":"Public Health Agency  Belfast UK"},{"name":"Centre for Public Health Queen's University Belfast  Belfast UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9765-3873","authenticated-orcid":false,"given":"Siobh\u00e1n","family":"Murphy","sequence":"additional","affiliation":[{"name":"Public Health Agency  Belfast UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mark G.","family":"O'Doherty","sequence":"additional","affiliation":[{"name":"Public Health Agency  Belfast UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Suzanne","family":"Wilton","sequence":"additional","affiliation":[{"name":"Public Health Agency  Belfast UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-3178-2550","authenticated-orcid":false,"given":"Emma","family":"Dickson","sequence":"additional","affiliation":[{"name":"Public Health Agency  Belfast UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1468-1823","authenticated-orcid":false,"given":"Declan T.","family":"Bradley","sequence":"additional","affiliation":[{"name":"Public Health Agency  Belfast UK"},{"name":"Centre for Public Health Queen's University Belfast  Belfast UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,8,6]]},"reference":[{"key":"e_1_2_12_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140\u20106736(17)30129\u20100"},{"issue":"14","key":"e_1_2_12_3_1","article-title":"Excess All\u2010Cause and Influenza\u2010Attributable Mortality in Europe, December 2016 to February 2017","volume":"22","author":"Vestergaard L. S.","year":"2016","journal-title":"Euro Surveillance: European Communicable Disease Bulletin"},{"key":"e_1_2_12_4_1","volume-title":"Surveillance Report: Seasonal influenza, 2023\u20132024","author":"European Centre for Disease Prevention and Control","year":"2025"},{"key":"e_1_2_12_5_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jiph.2025.102934"},{"key":"e_1_2_12_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/S1473-3099(16)00129-8"},{"issue":"4","key":"e_1_2_12_7_1","article-title":"Interim Estimates of Vaccine Effectiveness Against Influenza A (H1N1) pdm09 and A (H3N2) During a Delayed Influenza Season, Canada, 2024\/25","volume":"30","author":"Separovic L.","year":"2024","journal-title":"Eurosurveillance"},{"issue":"12","key":"e_1_2_12_8_1","article-title":"Enhanced Influenza Vaccines Impact Effectiveness in Individuals Aged 65\u2009Years and Older, Denmark, 2024\/25 Influenza Season up to 4 March 2025","volume":"30","author":"Emborg H. D.","year":"2024","journal-title":"Eurosurveillance"},{"key":"e_1_2_12_9_1","doi-asserted-by":"publisher","DOI":"10.2807\/1560-7917.ES.2025.30.7.2500102"},{"key":"e_1_2_12_10_1","doi-asserted-by":"publisher","DOI":"10.15585\/mmwr.mm7406a2"},{"key":"e_1_2_12_11_1","doi-asserted-by":"publisher","DOI":"10.1111\/irv.70115"},{"issue":"7","key":"e_1_2_12_12_1","article-title":"Influenza Vaccine Effectiveness Against Detected Infection in the Community, France, October 2024 to February 2025","volume":"30","author":"Blanquart F.","year":"2024","journal-title":"Euro Surveillance: European Communicable Disease Bulletin"},{"key":"e_1_2_12_13_1","volume-title":"2024\/25 Ni Influenza Annual Surveillance Report","author":"Public Health Agency","year":"2025"},{"key":"e_1_2_12_14_1","volume-title":"Seasonal Influenza Vaccination Programme 2024\/25 (Ref: HSS (MD) 33\/2024 [Letter]) (Ref: HSS (MD) 33\/2024 [Letter])","author":"Chief Medical Officer","year":"2024"},{"key":"e_1_2_12_15_1","volume-title":"Seasonal Influenza Vaccination Programme 2024\/25 \u2013 Extension to All Health and Social Care Workers (Ref: HSS (MD) 35\/2024 [Letter])","author":"Chief Medical Officer","year":"2024"},{"key":"e_1_2_12_16_1","volume-title":"Extension of Seasonal Influenza Vaccination Offer to all 50\u201364\u2009Year Olds (Ref: HSS (MD) 01\/2025 [Letter])","author":"Chief Medical Officer","year":"2025"},{"key":"e_1_2_12_17_1","volume-title":"Influenza Vaccination for High\u2010Risk Poultry and Avian Animal Health Workers (Ref: HSS (MD) 43\/2024 [Letter])","author":"Chief Medical Officer","year":"2024"},{"key":"e_1_2_12_18_1","volume-title":"Seasonal Influenza Vaccination Surveillance in Northern Ireland Autumn\/Winter 2024\/25","author":"Public Health Agency","year":"2025"},{"key":"e_1_2_12_19_1","doi-asserted-by":"publisher","DOI":"10.1093\/oxfordjournals.aje.a116397"},{"key":"e_1_2_12_20_1","doi-asserted-by":"publisher","DOI":"10.1111\/irv.70149"},{"key":"e_1_2_12_21_1","doi-asserted-by":"publisher","DOI":"10.1080\/22221751.2025.2562045"},{"key":"e_1_2_12_22_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jvacx.2025.100710"}],"container-title":["Influenza and Other Respiratory Viruses"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/irv.70303","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1111\/irv.70303","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/irv.70303","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T04:13:14Z","timestamp":1787631194000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/irv.70303"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8]]},"references-count":21,"journal-issue":{"issue":"8","published-print":{"date-parts":[[2026,8]]}},"alternative-id":["10.1111\/irv.70303"],"URL":"https:\/\/doi.org\/10.1111\/irv.70303","archive":["Portico"],"relation":{},"ISSN":["1750-2640","1750-2659"],"issn-type":[{"value":"1750-2640","type":"print"},{"value":"1750-2659","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8]]},"assertion":[{"value":"2026-02-20","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-08-03","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-08-06","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e70303"}}