{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,28]],"date-time":"2026-10-28T00:38:24Z","timestamp":1793147904272,"version":"4.5.0"},"reference-count":16,"publisher":"Wiley","issue":"8","license":[{"start":{"date-parts":[[2025,7,24]],"date-time":"2025-07-24T00:00:00Z","timestamp":1753315200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Medical Journal of Australia"],"published-print":{"date-parts":[[2025,10,20]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Objectives<\/jats:title><jats:p>To assess the effectiveness of the severe acute respiratory syndrome coronavirus 2 (SARS\u2010CoV\u20102) monovalent XBB.1.5 variant vaccine for reducing coronavirus disease 2019 (COVID\u201019) mortality among people aged 65 years or older.<\/jats:p><\/jats:sec><jats:sec><jats:title>Study design<\/jats:title><jats:p>Retrospective observational cohort study; analysis of linked 2021 Australian census, Australian Immunisation Register, and death registrations data.<\/jats:p><\/jats:sec><jats:sec><jats:title>Setting<\/jats:title><jats:p>Australia, 1 August 2023 to 29 February 2024; dominant SARS\u2010CoV\u20102 Omicron subvariants: XBB\u2010related until early December 2023, then the BA.2.86\u2010related JN.1.<\/jats:p><\/jats:sec><jats:sec><jats:title>Participants<\/jats:title><jats:p>People aged 65 years or older on 1 August 2023.<\/jats:p><\/jats:sec><jats:sec><jats:title>Main outcome measures<\/jats:title><jats:p>Relative vaccine effectiveness by time since most recent booster and booster type (XBB.1.5 variant or other), adjusted for age, gender, state\/territory, household income, number of medical conditions, number of general practice visits, and influenza vaccination during 2022.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>By 29 February 2024, 1620 COVID\u201019\u2010specific deaths among 4.12 million people aged 65 years or older had been recorded. COVID\u201019 mortality was lower among people who had received XBB.1.5 COVID\u201019 booster doses during the preceding 90 days (21 [95% confidence interval {CI}, 9\u201352] per 100\u2009000 person\u2010years) than among those whose most recent booster had been more than 365 days ago (72 [95% CI, 61\u201384] per 100\u2009000 person\u2010years). The relative vaccine effectiveness for XBB.1.5 boosters during the preceding 90 days (<jats:italic>v<\/jats:italic> any booster &gt;\u2009365 days) was 74.7% (95% CI, 59.9\u201384.1%); for other booster types it was 51.6% (95% CI, 39.3\u201361.4%). Relative vaccine effectiveness declined with time: for any booster during the preceding 91\u2013180 days (<jats:italic>v<\/jats:italic> any booster &gt;\u2009365 days) it was 31.2% (95% CI, 18.9\u201341.6%); for any booster during the preceding 181\u2013365 days it was 13.1% (95% CI, 1.8\u201323.2%). Relative XBB.1.5 vaccine effectiveness was similar in analyses restricted to 1 December 2023 \u2013 29 February 2024, when the dominant Omicron subvariant was JN.1.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>Recent booster vaccination with the XBB.1.5 monovalent COVID\u201019 vaccine was highly effective for preventing COVID\u201019 deaths among people aged 65 years or older, including during the period in which the JN.1 was the dominant SARS\u2010CoV\u20102 Omicron subvariant. Our findings provide support for the recommendation that people aged 65 years or older receive COVID\u201019 vaccine booster doses every six months.<\/jats:p><\/jats:sec>","DOI":"10.5694\/mja2.70015","type":"journal-article","created":{"date-parts":[[2025,7,24]],"date-time":"2025-07-24T08:21:44Z","timestamp":1753345304000},"page":"418-422","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Effectiveness of <scp>COVID<\/scp>\u201019 vaccine boosters for reducing <scp>COVID<\/scp>\u201019 mortality among people aged 65 years or older, Australia, August 2023 \u2013 February 2024: a retrospective observational cohort study"],"prefix":"10.5694","volume":"223","author":[{"given":"Bette","family":"Liu","sequence":"first","affiliation":[{"name":"National Centre for Immunisation Research and Surveillance (NCIRS) Children\u2019s Hospital at Westmead  Sydney NSW"},{"name":"University of New South Wales  Sydney NSW"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anish","family":"Scaria","sequence":"additional","affiliation":[{"name":"National Centre for Immunisation Research and Surveillance (NCIRS) Children\u2019s Hospital at Westmead  Sydney NSW"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sandrine","family":"Stepien","sequence":"additional","affiliation":[{"name":"National Centre for Immunisation Research and Surveillance (NCIRS) Children\u2019s Hospital at Westmead  Sydney NSW"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4675-0232","authenticated-orcid":false,"given":"Kristine","family":"Macartney","sequence":"additional","affiliation":[{"name":"National Centre for Immunisation Research and Surveillance (NCIRS) Children\u2019s Hospital at Westmead  Sydney NSW"},{"name":"The University of Sydney  Sydney NSW"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2025,7,24]]},"reference":[{"key":"e_1_2_9_1_1","unstructured":"World Health Organization.Statement on the antigen composition of COVID\u201019 vaccines. 13 Dec2023.https:\/\/www.who.int\/news\/item\/13\u201012\u20102023\u2010statement\u2010on\u2010the\u2010antigen\u2010composition\u2010of\u2010covid\u201019\u2010vaccines(viewed Aug 2024)."},{"key":"e_1_2_9_2_1","unstructured":"Australian Department of Health Disability and Ageing.ATAGI recommendations on use of the Moderna and Pfizer monovalent Omicron XBB.1.5 COVID\u201019 vaccines [media release]. 20 Nov2023.https:\/\/www.health.gov.au\/news\/atagi\u2010recommendations\u2010on\u2010use\u2010of\u2010the\u2010moderna\u2010and\u2010pfizer\u2010monovalent\u2010omicron\u2010xbb15\u2010covid\u201019\u2010vaccines(viewed June 2024)."},{"key":"e_1_2_9_3_1","doi-asserted-by":"publisher","DOI":"10.15585\/mmwr.mm7304a2"},{"key":"e_1_2_9_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/S1473-3099(23)00746-6"},{"key":"e_1_2_9_5_1","first-page":"48","article-title":"COVID\u201019 Australia: epidemiology report 85. Reporting period ending 10 March 2024","author":"Viral Respiratory Diseases Epidemiology and Surveillance Team","journal-title":"Commun Dis Intell"},{"key":"e_1_2_9_6_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMc2402779"},{"key":"e_1_2_9_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jinf.2024.106177"},{"key":"e_1_2_9_8_1","doi-asserted-by":"publisher","DOI":"10.1136\/bmjmed-2024-001074"},{"key":"e_1_2_9_9_1","doi-asserted-by":"publisher","DOI":"10.1111\/irv.13292"},{"key":"e_1_2_9_10_1","unstructured":"Australian Department of Health Disability and Ageing [media release].ATAGI update on the COVID\u201019 vaccination program. 1 Sept2023.https:\/\/www.health.gov.au\/news\/atagi\u2010update\u2010on\u2010the\u2010covid\u201019\u2010vaccination\u2010program(viewed June 2024)."},{"key":"e_1_2_9_11_1","article-title":"Effectiveness of COVID\u201019 vaccination against COVID\u201019 specific and all\u2010cause mortality in older Australians: a population based study","volume":"40","author":"Liu B","year":"2023","journal-title":"Lancet Reg Health West Pac"},{"key":"e_1_2_9_12_1","unstructured":"Australian Bureau of Statistics.Person level integrated data asset (PLIDA). Undated.https:\/\/www.abs.gov.au\/about\/data\u2010services\/data\u2010integration\/integrated\u2010data\/person\u2010level\u2010integrated\u2010data\u2010asset\u2010plida(viewed June 2024)."},{"key":"e_1_2_9_13_1","unstructured":"Australian Department of Health and Aged Care.COVID\u201019 vaccine rollout. 10 Jan2024.https:\/\/www.health.gov.au\/sites\/default\/files\/2024\u201001\/covid\u201019\u2010vaccine\u2010rollout\u2010update\u201012\u2010january\u20102024.pdf(viewed July 2025)."},{"key":"e_1_2_9_14_1","doi-asserted-by":"publisher","DOI":"10.1136\/bmjopen-2017-021122"},{"key":"e_1_2_9_15_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.eclinm.2024.102995"},{"key":"e_1_2_9_16_1","unstructured":"World Health Organization.Statement on the antigen composition of COVID\u201019 vaccines. 15 May2025.https:\/\/www.who.int\/news\/item\/15\u201005\u20102025\u2010statement\u2010on\u2010the\u2010antigen\u2010composition\u2010of\u2010covid\u201019\u2010vaccines(viewed July 2025)."}],"container-title":["Medical Journal of Australia"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.5694\/mja2.70015","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,20]],"date-time":"2025-10-20T04:41:11Z","timestamp":1760935271000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.5694\/mja2.70015"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,7,24]]},"references-count":16,"journal-issue":{"issue":"8","published-print":{"date-parts":[[2025,10,20]]}},"alternative-id":["10.5694\/mja2.70015"],"URL":"https:\/\/doi.org\/10.5694\/mja2.70015","archive":["Portico"],"relation":{},"ISSN":["0025-729X","1326-5377"],"issn-type":[{"value":"0025-729X","type":"print"},{"value":"1326-5377","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,7,24]]},"assertion":[{"value":"2024-08-07","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-03-26","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-07-24","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}