{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T19:08:26Z","timestamp":1782846506893,"version":"3.54.5"},"reference-count":38,"publisher":"JMIR Publications Inc.","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JMIR Public Health Surveill"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec sec-type=\"background\">\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>A large wave of COVID-19 caused by SARS-CoV-2 Omicron subvariants began in Beijing in early December 2022.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec sec-type=\"objective\">\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>This study aimed to evaluate the COVID-19 vaccine effectiveness (VE) in mitigating the risk of COVID-19\u2013related hospitalization during the epidemic.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec sec-type=\"methods\">\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We conducted a retrospective cohort study linking regional health care data and vaccination registry routinely collected in Beijing. All electronic medical records on COVID-19\u2013related hospital discharges of older inpatients aged \u226580 years during November 2022 and February 2023 were included. Poisson regressions were used to estimate incidence risk ratio of COVID-19\u2013related hospitalization, severe or critical cases, and in-hospital death compared with unvaccinated groups, adjusting for gender and age. VE was calculated as 1 minus incidence risk ratio\u00d7100%.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec sec-type=\"results\">\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>A total of 53,789 individuals aged \u226580 years were included, 28,423 (52.84%) were male, 45,270 (84.16%) were aged 80\u201089 years, and 8519 (15.84%) were aged \u226590 years. Overall, 30,531 (56.76%) were in the vaccine group, with 4524 (8.41%) of the total participants receiving partial vaccination, 20.91% completing the primary series, and 14,761 (27.44%) receiving one booster. Additionally, 23,258 (43.24%) were in the unvaccinated group. Of the 53,789 hospitalized individuals, 17,916 (33.31%) had a COVID-19 diagnosis, 3535 (6.57%) had COVID-19\u2013related hospitalization, 961 (1.79%) were COVID-19 severe or critical cases, and 4130 (7.68%) had in-hospital death. The analysis revealed that the VE of booster vaccination in preventing COVID-19\u2013related hospital, severe or critical COVID-19, and in-hospital death was 63.5% (95% CI 59.8%\u201066.9%), 66.9% (95% CI 60.1%\u201072.6%) and 79.4% (95% CI 77%\u201081.5%), the VE of primary series 56% (95% CI 51.4%\u201060.2%), 66.8% (95% CI 59%\u201073%) and 66.4% (95% CI 63%\u201069.5%).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec sec-type=\"conclusions\">\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>The first booster vaccination was associated with significantly reduced the risk of COVID-19\u2013related severe outcomes in older inpatients aged \u226580 years during the Omicron-dominant period. Considering the potential selection bias and unmeasured confounders, these estimates may reflect both the VE and the better baseline health status of the vaccinated older individuals.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.2196\/82915","type":"journal-article","created":{"date-parts":[[2026,3,11]],"date-time":"2026-03-11T20:16:07Z","timestamp":1773260167000},"page":"e82915-e82915","source":"Crossref","is-referenced-by-count":0,"title":["Effectiveness of Inactivated COVID-19 Vaccination Against COVID-19\u2013Related Hospitalization and Severe Outcomes in Adults \u226580 Years During Omicron Circulation in Beijing, China: Retrospective Cohort Study"],"prefix":"10.2196","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5840-8071","authenticated-orcid":false,"given":"Dan","family":"Zhao","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-5565-5249","authenticated-orcid":false,"given":"Ying","family":"Ma","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-7878-2018","authenticated-orcid":false,"given":"Juan","family":"Li","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4909-3442","authenticated-orcid":false,"given":"Xiaomei","family":"Li","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-4585-8337","authenticated-orcid":false,"given":"Zhiqiang","family":"Cao","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-9869-0711","authenticated-orcid":false,"given":"Wei","family":"Yao","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8505-4723","authenticated-orcid":false,"given":"Jiang","family":"Wu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-0634-1666","authenticated-orcid":false,"given":"Luodan","family":"Suo","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1010","published-online":{"date-parts":[[2026,3,11]]},"reference":[{"key":"R1","unstructured":"Coronavirus disease (COVID-19). World Health Organization. URL: https:\/\/www.who.int\/news-room\/fact-sheets\/detail\/coronavirus-disease-(covid-19) [Accessed 20-12-2023]"},{"issue":"7923","key":"R2","doi-asserted-by":"publisher","first-page":"593","DOI":"10.1038\/s41586-022-04980-y","article-title":"BA.2.12.1, BA.4 and BA.5 escape antibodies elicited by Omicron infection","volume":"608","author":"Cao","journal-title":"Nature New Biol"},{"issue":"1","key":"R3","doi-asserted-by":"publisher","first-page":"86","DOI":"10.1056\/NEJMc2206576","article-title":"Neutralization escape by SARS-CoV-2 Omicron subvariants BA.2.12.1, BA.4, and BA.5","volume":"387","author":"Hachmann","journal-title":"N Engl J Med"},{"key":"R4","unstructured":"WHO roadmap on uses of COVID-19 vaccines in the context of Omicron and high population immunity. World Health Organization. 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The Portal Website of the Central People\u2019s Government of the People\u2019s Republic of China. 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