{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,6]],"date-time":"2026-11-06T23:28:04Z","timestamp":1794007684461,"version":"4.8.0"},"reference-count":19,"publisher":"SAGE Publications","issue":"5","license":[{"start":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T00:00:00Z","timestamp":1790812800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"funder":[{"name":"South Australian Department for Health and Wellbeing"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Health Security"],"published-print":{"date-parts":[[2026,10,1]]},"abstract":"<jats:p>On November 23, 2021, South Australia lifted border restrictions allowing passive entry of COVID-19 cases into the community. On this date the adult South Australian population was highly vaccinated and COVID-19 na\u00efve (prior infection rate &lt;1:1000). There are no previous outcome data following introduction of SARS-CoV-2 to a susceptible population that was highly vaccinated. The aim of this study was to measure the effect of sole vaccine-derived immunity against SARS-CoV-2, in a virus-na\u00efve population without prior community transmission. This retrospective cohort study of 132,579 adults with COVID-19 was conducted between November 2021 and March 2022. The primary outcome was in-hospital mortality; secondary outcomes were hospital and intensive care unit admission, stratified by vaccination status. Risk-adjusted multivariable logistic regression analysis was performed using a Bayesian framework. Unvaccinated patients had increased odds of death (OR 3.78, 95% credible interval [CrI] 1.20 to 10.58, Bayesian probability of effect [Pr] 0.99), hospital admission (OR 23.9, 95% CrI 19.38 to 29.13, Pr 1.0), and ICU admission (OR 4.68, 95% CrI 1.58 to 12.34, Pr 1.0). Exclusively vaccine-derived immunity against SARS-CoV-2 is unequivocally protective against hospitalization and death. South Australia\u2019s pandemic response may be informative in planning for future pandemics, and management of future variants of SARS-CoV-2.<\/jats:p>","DOI":"10.1177\/23265094261480546","type":"journal-article","created":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T04:29:02Z","timestamp":1791433742000},"page":"376-384","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":0,"title":["Inpatient Outcomes in a SARS-CoV-2 Na\u00efve Population Achieving High Vaccination Coverage Preceding Planned Virus Entry: A Prospective, Natural Experiment, Pandemic Response Cohort Study"],"prefix":"10.1177","volume":"24","author":[{"given":"Eamon P.","family":"Raith","sequence":"first","affiliation":[{"name":"Eamon P. Raith, MBBS, PhD, FCICM, is an Associate Professor and Research Lead at Mackay Clinical School, College of Medicine and Dentistry, James Cook University, Queensland; an ICU Consultant, Department of Intensive Care Services, Mackay Hospital and Health Service, Mackay, Queensland; a Senior Fellow, Critical Care Research Group, Prince Charles Hospital, Chermside, Queensland; an Adjunct Senior Research Fellow, Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria; and a Clinical Senior Lecturer, School of Medicine, College of Health, Adelaide University, South Australia. Krishnaswamy Sundararajan, MD, FCICM, is Director, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, School of Medicine, College of Health, Adelaide University, Adelaide, South Australia. Mark Plummer, MBBS, PhD, FCICM, is Head of Research and Innovation, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, Scho..."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hao Z.","family":"Wong","sequence":"additional","affiliation":[{"name":"Eamon P. Raith, MBBS, PhD, FCICM, is an Associate Professor and Research Lead at Mackay Clinical School, College of Medicine and Dentistry, James Cook University, Queensland; an ICU Consultant, Department of Intensive Care Services, Mackay Hospital and Health Service, Mackay, Queensland; a Senior Fellow, Critical Care Research Group, Prince Charles Hospital, Chermside, Queensland; an Adjunct Senior Research Fellow, Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria; and a Clinical Senior Lecturer, School of Medicine, College of Health, Adelaide University, South Australia. Krishnaswamy Sundararajan, MD, FCICM, is Director, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, School of Medicine, College of Health, Adelaide University, Adelaide, South Australia. Mark Plummer, MBBS, PhD, FCICM, is Head of Research and Innovation, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, Scho..."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joshua V.","family":"Ross","sequence":"additional","affiliation":[{"name":"Eamon P. Raith, MBBS, PhD, FCICM, is an Associate Professor and Research Lead at Mackay Clinical School, College of Medicine and Dentistry, James Cook University, Queensland; an ICU Consultant, Department of Intensive Care Services, Mackay Hospital and Health Service, Mackay, Queensland; a Senior Fellow, Critical Care Research Group, Prince Charles Hospital, Chermside, Queensland; an Adjunct Senior Research Fellow, Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria; and a Clinical Senior Lecturer, School of Medicine, College of Health, Adelaide University, South Australia. Krishnaswamy Sundararajan, MD, FCICM, is Director, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, School of Medicine, College of Health, Adelaide University, Adelaide, South Australia. Mark Plummer, MBBS, PhD, FCICM, is Head of Research and Innovation, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, Scho..."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Samuel","family":"Ziesing","sequence":"additional","affiliation":[{"name":"Eamon P. Raith, MBBS, PhD, FCICM, is an Associate Professor and Research Lead at Mackay Clinical School, College of Medicine and Dentistry, James Cook University, Queensland; an ICU Consultant, Department of Intensive Care Services, Mackay Hospital and Health Service, Mackay, Queensland; a Senior Fellow, Critical Care Research Group, Prince Charles Hospital, Chermside, Queensland; an Adjunct Senior Research Fellow, Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria; and a Clinical Senior Lecturer, School of Medicine, College of Health, Adelaide University, South Australia. Krishnaswamy Sundararajan, MD, FCICM, is Director, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, School of Medicine, College of Health, Adelaide University, Adelaide, South Australia. Mark Plummer, MBBS, PhD, FCICM, is Head of Research and Innovation, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, Scho..."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Imogen","family":"Asser","sequence":"additional","affiliation":[{"name":"Eamon P. Raith, MBBS, PhD, FCICM, is an Associate Professor and Research Lead at Mackay Clinical School, College of Medicine and Dentistry, James Cook University, Queensland; an ICU Consultant, Department of Intensive Care Services, Mackay Hospital and Health Service, Mackay, Queensland; a Senior Fellow, Critical Care Research Group, Prince Charles Hospital, Chermside, Queensland; an Adjunct Senior Research Fellow, Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria; and a Clinical Senior Lecturer, School of Medicine, College of Health, Adelaide University, South Australia. Krishnaswamy Sundararajan, MD, FCICM, is Director, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, School of Medicine, College of Health, Adelaide University, Adelaide, South Australia. Mark Plummer, MBBS, PhD, FCICM, is Head of Research and Innovation, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, Scho..."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael","family":"Maclean","sequence":"additional","affiliation":[{"name":"Eamon P. Raith, MBBS, PhD, FCICM, is an Associate Professor and Research Lead at Mackay Clinical School, College of Medicine and Dentistry, James Cook University, Queensland; an ICU Consultant, Department of Intensive Care Services, Mackay Hospital and Health Service, Mackay, Queensland; a Senior Fellow, Critical Care Research Group, Prince Charles Hospital, Chermside, Queensland; an Adjunct Senior Research Fellow, Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria; and a Clinical Senior Lecturer, School of Medicine, College of Health, Adelaide University, South Australia. Krishnaswamy Sundararajan, MD, FCICM, is Director, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, School of Medicine, College of Health, Adelaide University, Adelaide, South Australia. Mark Plummer, MBBS, PhD, FCICM, is Head of Research and Innovation, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, Scho..."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Krishnaswamy","family":"Sundararajan","sequence":"additional","affiliation":[{"name":"Eamon P. Raith, MBBS, PhD, FCICM, is an Associate Professor and Research Lead at Mackay Clinical School, College of Medicine and Dentistry, James Cook University, Queensland; an ICU Consultant, Department of Intensive Care Services, Mackay Hospital and Health Service, Mackay, Queensland; a Senior Fellow, Critical Care Research Group, Prince Charles Hospital, Chermside, Queensland; an Adjunct Senior Research Fellow, Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria; and a Clinical Senior Lecturer, School of Medicine, College of Health, Adelaide University, South Australia. Krishnaswamy Sundararajan, MD, FCICM, is Director, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, School of Medicine, College of Health, Adelaide University, Adelaide, South Australia. Mark Plummer, MBBS, PhD, FCICM, is Head of Research and Innovation, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, Scho..."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lauren","family":"Fielke","sequence":"additional","affiliation":[{"name":"Eamon P. Raith, MBBS, PhD, FCICM, is an Associate Professor and Research Lead at Mackay Clinical School, College of Medicine and Dentistry, James Cook University, Queensland; an ICU Consultant, Department of Intensive Care Services, Mackay Hospital and Health Service, Mackay, Queensland; a Senior Fellow, Critical Care Research Group, Prince Charles Hospital, Chermside, Queensland; an Adjunct Senior Research Fellow, Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria; and a Clinical Senior Lecturer, School of Medicine, College of Health, Adelaide University, South Australia. Krishnaswamy Sundararajan, MD, FCICM, is Director, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, School of Medicine, College of Health, Adelaide University, Adelaide, South Australia. Mark Plummer, MBBS, PhD, FCICM, is Head of Research and Innovation, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, Scho..."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shailesh","family":"Bihari","sequence":"additional","affiliation":[{"name":"Eamon P. Raith, MBBS, PhD, FCICM, is an Associate Professor and Research Lead at Mackay Clinical School, College of Medicine and Dentistry, James Cook University, Queensland; an ICU Consultant, Department of Intensive Care Services, Mackay Hospital and Health Service, Mackay, Queensland; a Senior Fellow, Critical Care Research Group, Prince Charles Hospital, Chermside, Queensland; an Adjunct Senior Research Fellow, Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria; and a Clinical Senior Lecturer, School of Medicine, College of Health, Adelaide University, South Australia. Krishnaswamy Sundararajan, MD, FCICM, is Director, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, School of Medicine, College of Health, Adelaide University, Adelaide, South Australia. Mark Plummer, MBBS, PhD, FCICM, is Head of Research and Innovation, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, Scho..."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Caroline","family":"Miller","sequence":"additional","affiliation":[{"name":"Eamon P. Raith, MBBS, PhD, FCICM, is an Associate Professor and Research Lead at Mackay Clinical School, College of Medicine and Dentistry, James Cook University, Queensland; an ICU Consultant, Department of Intensive Care Services, Mackay Hospital and Health Service, Mackay, Queensland; a Senior Fellow, Critical Care Research Group, Prince Charles Hospital, Chermside, Queensland; an Adjunct Senior Research Fellow, Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria; and a Clinical Senior Lecturer, School of Medicine, College of Health, Adelaide University, South Australia. Krishnaswamy Sundararajan, MD, FCICM, is Director, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, School of Medicine, College of Health, Adelaide University, Adelaide, South Australia. Mark Plummer, MBBS, PhD, FCICM, is Head of Research and Innovation, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, Scho..."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicola","family":"Spurrier","sequence":"additional","affiliation":[{"name":"Eamon P. Raith, MBBS, PhD, FCICM, is an Associate Professor and Research Lead at Mackay Clinical School, College of Medicine and Dentistry, James Cook University, Queensland; an ICU Consultant, Department of Intensive Care Services, Mackay Hospital and Health Service, Mackay, Queensland; a Senior Fellow, Critical Care Research Group, Prince Charles Hospital, Chermside, Queensland; an Adjunct Senior Research Fellow, Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria; and a Clinical Senior Lecturer, School of Medicine, College of Health, Adelaide University, South Australia. Krishnaswamy Sundararajan, MD, FCICM, is Director, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, School of Medicine, College of Health, Adelaide University, Adelaide, South Australia. Mark Plummer, MBBS, PhD, FCICM, is Head of Research and Innovation, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, Scho..."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mark","family":"Plummer","sequence":"additional","affiliation":[{"name":"Eamon P. Raith, MBBS, PhD, FCICM, is an Associate Professor and Research Lead at Mackay Clinical School, College of Medicine and Dentistry, James Cook University, Queensland; an ICU Consultant, Department of Intensive Care Services, Mackay Hospital and Health Service, Mackay, Queensland; a Senior Fellow, Critical Care Research Group, Prince Charles Hospital, Chermside, Queensland; an Adjunct Senior Research Fellow, Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria; and a Clinical Senior Lecturer, School of Medicine, College of Health, Adelaide University, South Australia. Krishnaswamy Sundararajan, MD, FCICM, is Director, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, School of Medicine, College of Health, Adelaide University, Adelaide, South Australia. Mark Plummer, MBBS, PhD, FCICM, is Head of Research and Innovation, Department of Intensive Care Medicine, Royal Adelaide Hospital, and an Associate Professor, Scho..."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2026,10,7]]},"reference":[{"key":"e_1_3_2_2_1","unstructured":"1.Australian Government Department of Health and Ageing. COVID-19 vaccine rollout update \u2013 jurisdictional breakdown. 24 November 2021. Accessed May 12 2023. https:\/\/www.health.gov.au\/resources\/publications\/covid-19-vaccine-rollout-update-jurisdictional-breakdown-24-november-2021?language=en"},{"key":"e_1_3_2_3_1","unstructured":"2.Australian Government Department of Health Disability and Ageing. ATAGI clinical guidance for COVID-19 vaccine providers. Updated June 18 2025. Accessed July 27 2026. https:\/\/www.health.gov.au\/our-work\/covid-19-vaccines\/advice-for-providers\/clinical-guidance"},{"key":"e_1_3_2_4_1","unstructured":"3.Australian National Audit Office. Australia\u2019s Covid\u201019 vaccine rollout. Published August 17 2022. Accessed July 27 2026. https:\/\/www.anao.gov.au\/work\/performance-audit\/australia-covid-19-vaccine-rollout"},{"key":"e_1_3_2_5_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa2115624"},{"issue":"12","key":"e_1_3_2_6_1","first-page":"CD015477","article-title":"Efficacy and safety of COVID\u201019 vaccines","volume":"12","author":"Gra\u00f1a C","year":"2022","unstructured":"5.Gra\u00f1a C, , Ghosn L, , Evrenoglou T, et al. Efficacy and safety of COVID\u201019 vaccines. Cochrane Database Syst Rev. 2022;12(12):CD015477.","journal-title":"Cochrane Database Syst Rev"},{"key":"e_1_3_2_7_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa2035389"},{"key":"e_1_3_2_8_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41591-023-02219-5"},{"key":"e_1_3_2_9_1","unstructured":"8.Australian Bureau of Statistics. Socio-Economic Indexes for Areas (SEIFA) Australia. Accessed May 12 2023. https:\/\/www.abs.gov.au\/statistics\/people\/people-and-communities\/socio-economic-indexes-areas-seifa-australia\/latest-release"},{"key":"e_1_3_2_10_1","doi-asserted-by":"publisher","DOI":"10.1111\/imj.15106"},{"key":"e_1_3_2_11_1","doi-asserted-by":"publisher","DOI":"10.3389\/fpubh.2021.676843"},{"key":"e_1_3_2_12_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(20)31097-7"},{"key":"e_1_3_2_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijsu.2020.04.018"},{"key":"e_1_3_2_14_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa2200674"},{"key":"e_1_3_2_15_1","doi-asserted-by":"publisher","DOI":"10.1002\/jmv.25783"},{"key":"e_1_3_2_16_1","doi-asserted-by":"publisher","DOI":"10.1111\/imj.14963"},{"key":"e_1_3_2_17_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0252898"},{"key":"e_1_3_2_18_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa1404380"},{"key":"e_1_3_2_19_1","doi-asserted-by":"publisher","DOI":"10.1001\/jama.2016.20328"},{"key":"e_1_3_2_20_1","doi-asserted-by":"publisher","DOI":"10.1016\/S2213-2600(22)00045-5"}],"container-title":["Health Security"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/23265094261480546","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/full-xml\/10.1177\/23265094261480546","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/23265094261480546","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,11,6]],"date-time":"2026-11-06T23:16:13Z","timestamp":1794006973000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/10.1177\/23265094261480546"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,1]]},"references-count":19,"journal-issue":{"issue":"5","published-print":{"date-parts":[[2026,10,1]]}},"alternative-id":["10.1177\/23265094261480546"],"URL":"https:\/\/doi.org\/10.1177\/23265094261480546","relation":{},"ISSN":["2326-5094","2326-5108"],"issn-type":[{"value":"2326-5094","type":"print"},{"value":"2326-5108","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,10,1]]}}}