{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,16]],"date-time":"2026-04-16T16:19:39Z","timestamp":1776356379257,"version":"3.51.2"},"reference-count":51,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2023,2,8]],"date-time":"2023-02-08T00:00:00Z","timestamp":1675814400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Med."],"abstract":"<jats:sec><jats:title>Objectives<\/jats:title><jats:p>To evaluate COVID-19 vaccines in primary prevention against infections and lessen the severity of illness following the most recent outbreak of the SARS-CoV-2 Omicron variant in Shanghai.<\/jats:p><\/jats:sec><jats:sec><jats:title>Data sources<\/jats:title><jats:p>Data from 153,544 COVID-19 patients admitted to the Shanghai \u201cFour-Leaf Clover\u201d Fangcang makeshift shelter hospital were collected using a structured electronic questionnaire, which was then merged with electronic medical records of the hospital. For healthy controls, data on vaccination status and other information were obtained from 228 community-based residents, using the same structured electronic questionnaire.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>To investigate whether inactivated vaccines were effective in protecting against SARS-CoV-2 virus, we estimated the odds ratio (OR) of the vaccination by comparing cases and matched community-based healthy controls. To evaluate the potential benefits of vaccination in lowering the risk of symptomatic infection (vs. asymptomatic), we estimated the relative risk (RR) of symptomatic infections among diagnosed patients. We also applied multivariate stepwise logistic regression analyses to measure the risk of disease severity (symptomatic vs. asymptomatic and moderate\/severe vs. mild) in the COVID-19 patient cohort with vaccination status as an independent variable while controlling for potential confounding factors.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Of the 153,544 COVID-19 patients included in the analysis, the mean age was 41.59\u2009years and 90,830 were males (59.2%). Of the study cohort, 118,124 patients had been vaccinated (76.9%) and 143,225 were asymptomatic patients (93.3%). Of the 10,319 symptomatic patients, 10,031 (97.2%), 281 (2.7%), and 7 (0.1%) experienced mild, moderate, and severe infections, respectively. Hypertension (8.7%) and diabetes (3.0%) accounted for the majority of comorbidities. There is no evidence that the vaccination helped protect from infections (OR\u2009=\u20090.82, <jats:italic>p<\/jats:italic>\u2009=\u20090.613). Vaccination, however, offered a small but significant protection against symptomatic infections (RR\u2009=\u20090.92, <jats:italic>p<\/jats:italic>\u2009&amp;lt;\u20090.001) and halved the risk of moderate\/severe infections (OR\u2009=\u20090.48, 95% CI: 0.37\u20130.61). Older age (\u226560\u2009years) and malignant tumors were significantly associated with moderate\/severe infections.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>Inactivated COVID-19 vaccines helped provide small but significant protection against symptomatic infections and halved the risk of moderate\/severe illness among symptomatic patients. The vaccination was not effective in blocking the SARS-CoV-2 Omicron Variant community spread.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fmed.2023.1079165","type":"journal-article","created":{"date-parts":[[2023,2,8]],"date-time":"2023-02-08T16:53:46Z","timestamp":1675875226000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":5,"title":["Evaluation of COVID-19 vaccines in primary prevention against infections and reduction in severity of illness following the outbreak of SARS-CoV-2 omicron variant in Shanghai"],"prefix":"10.3389","volume":"10","author":[{"given":"Dawei","family":"Yang","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Huifen","family":"Weng","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rui","family":"Wang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"You","family":"Li","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hao","family":"Zhang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shifeng","family":"Shao","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hunan","family":"Huang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuanlin","family":"Song","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xiaoyan","family":"Chen","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dongni","family":"Hou","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yin","family":"Wu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xingwei","family":"Lu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wei","family":"Yang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhengguo","family":"Chen","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xiaohan","family":"Hu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jianwei","family":"Xuan","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chunxue","family":"Bai","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yaoli","family":"Wang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2023,2,8]]},"reference":[{"key":"ref1","year":"2022"},{"key":"ref2","year":"2022"},{"key":"ref3","year":"2022"},{"key":"ref4","doi-asserted-by":"publisher","first-page":"437","DOI":"10.1016\/S0140-6736(22)00017-4","article-title":"Early assessment of the clinical severity of the SARS-CoV-2 omicron variant in South Africa: a data linkage study","volume":"399","author":"Wolter","year":"2022","journal-title":"Lancet"},{"key":"ref5","volume-title":"Classification of Omicron (B.1.1.529): SARS-CoV-2 Variant of Concern","year":"2021"},{"key":"ref6","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","year":"2022","journal-title":"N Engl J Med."},{"key":"ref7","doi-asserted-by":"publisher","first-page":"4593","DOI":"10.1002\/jmv.27945","article-title":"Emergence of SARS-CoV-2 omicron BA.5 variant of concern in Western Pennsylvania, United States","volume":"94","author":"Phan","year":"2022","journal-title":"J Med Virol."},{"key":"ref8","doi-asserted-by":"publisher","first-page":"taab124","DOI":"10.1093\/jtm\/taab124","article-title":"The reproductive number of the Delta variant of SARS-CoV-2 is far higher compared to the ancestral SARS-CoV-2 virus","volume":"28","author":"Liu","year":"2021","journal-title":"J Travel Med."},{"key":"ref9","doi-asserted-by":"publisher","first-page":"46","DOI":"10.1016\/j.ajem.2022.01.028","article-title":"Clinical update on COVID-19 for the emergency clinician: presentation and evaluation","volume":"54","author":"Long","year":"2022","journal-title":"Am J Emerg Med."},{"key":"ref10","volume-title":"SARS-CoV-2 Variants of Concern and Variants under Investigation in England-Thechnial briefing","year":"2022"},{"key":"ref11","first-page":"3992","article-title":"Virological characteristics of the SARS-CoV-2 Omicron BA.2 subvariants, including BA.4 and BA.5","volume-title":"Cell","author":"Kimura","year":"2022"},{"key":"ref12","author":"Lyngse","year":"2022"},{"key":"ref13","doi-asserted-by":"publisher","first-page":"o263","DOI":"10.1136\/bmj.o263","article-title":"Omicron sub-lineage BA.2 may have substantial growth advantage, UKHSA reports","volume":"376","author":"Mahase","year":"2022","journal-title":"BMJ"},{"key":"ref14","doi-asserted-by":"publisher","first-page":"n3103","DOI":"10.1136\/bmj.n3103","article-title":"Covid-19: runny nose, headache, and fatigue are commonest symptoms of omicron, early data show","volume":"375","author":"Iacobucci","year":"2021","journal-title":"BMJ"},{"key":"ref15","volume-title":"What Are the Symptoms of Omicron?","year":"2022"},{"key":"ref16","doi-asserted-by":"publisher","first-page":"564","DOI":"10.1111\/tmi.13752","article-title":"Outcomes of laboratory-confirmed SARS-CoV-2 infection in the omicron-driven fourth wave compared with previous waves in the Western Cape Province, South Africa","volume":"27","author":"Davies","year":"2022","journal-title":"medRxiv"},{"key":"ref17","doi-asserted-by":"publisher","first-page":"38","DOI":"10.1016\/j.ijid.2021.12.357","article-title":"Decreased severity of disease during the first global omicron variant covid-19 outbreak in a large hospital in tshwane, South Africa","volume":"116","author":"Abdullah","year":"2022","journal-title":"Int J Infect Dis."},{"key":"ref18","doi-asserted-by":"publisher","first-page":"1286","DOI":"10.1001\/jama.2022.2274","article-title":"Estimates of SARS-CoV-2 omicron variant severity in Ontario","volume":"327","author":"Ulloa","year":"2022","journal-title":"Canada JAMA"},{"key":"ref19","doi-asserted-by":"publisher","first-page":"706","DOI":"10.1038\/s41586-022-04474-x","article-title":"Altered TMPRSS2 usage by SARS-CoV-2 omicron impacts infectivity and fusogenicity","volume":"603","author":"Meng","year":"2022","journal-title":"Nature"},{"key":"ref20","doi-asserted-by":"publisher","first-page":"715","DOI":"10.1038\/s41586-022-04479-6","article-title":"SARS-CoV-2 omicron variant replication in human bronchus and lung ex 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Republic of China. Coronavirus (COVID-19) Vaccinations","year":"2022"},{"key":"ref30","volume-title":"Coronavirus (COVID-19) Vaccinations","year":"2022"},{"key":"ref31","doi-asserted-by":"publisher","first-page":"35","DOI":"10.1001\/jama.2021.8565","article-title":"Effect of 2 inactivated SARS-CoV-2 vaccines on symptomatic COVID-19 infection in adults: a randomized clinical trial","volume":"326","author":"Al Kaabi","year":"2021","journal-title":"JAMA."},{"key":"ref32","doi-asserted-by":"publisher","first-page":"924","DOI":"10.1016\/S0140-6736(22)00152-0","article-title":"Duration of effectiveness of vaccines against SARS-CoV-2 infection and COVID-19 disease: results of a systematic review and meta-regression","volume":"399","author":"Feikin","year":"2022","journal-title":"Lancet."},{"key":"ref33","doi-asserted-by":"publisher","first-page":"e070102","DOI":"10.1136\/bmj-2022-070102","article-title":"Change in COVID-19 risk over time following vaccination with CoronaVac: test negative case-control study","volume":"377","author":"Hitchings","year":"2022","journal-title":"BMJ."},{"key":"ref34","doi-asserted-by":"publisher","first-page":"831","DOI":"10.1038\/s41591-022-01699-1","article-title":"Effectiveness of COVID-19 booster vaccines against COVID-19-related symptoms, hospitalization and death in England","volume":"28","author":"Andrews","year":"2022","journal-title":"Nat Med."},{"key":"ref35","doi-asserted-by":"publisher","first-page":"1393","DOI":"10.1056\/NEJMoa2114255","article-title":"Protection of BNT162b2 vaccine booster against COVID-19 in Israel","volume":"385","author":"Bar-On","year":"2021","journal-title":"N Engl J Med."},{"key":"ref36","doi-asserted-by":"publisher","first-page":"103","DOI":"10.1038\/s41422-021-00590-x","article-title":"Recombinant protein subunit vaccine booster following two-dose inactivated vaccines dramatically enhanced anti-RBD responses and neutralizing titers against SARS-CoV-2 and variants of concern","volume":"32","author":"Ai","year":"2022","journal-title":"Cell Res."},{"key":"ref37","doi-asserted-by":"publisher","first-page":"377","DOI":"10.46234\/ccdcw2022.081","article-title":"Preliminary study of the protectiveness of vaccination against the COVID-19 in the outbreak of VOC omicron BA.2 \u2013 Jilin City, Jilin Province, China, March 3-April 12, 2022","volume":"4","author":"Fan","year":"2022","journal-title":"China CDC Wkly."},{"key":"ref38","doi-asserted-by":"publisher","first-page":"n2244","DOI":"10.1136\/bmj.n2244","article-title":"Risk prediction of COVID-19 related death and hospital admission in adults after COVID-19 vaccination: national prospective cohort study","volume":"374","author":"Hippisley-Cox","year":"2021","journal-title":"BMJ"},{"key":"ref39","doi-asserted-by":"publisher","first-page":"e206","DOI":"10.1093\/cid\/ciaa1012","article-title":"Risk factors for intensive care unit admission and in-hospital mortality among hospitalized adults identified through the US coronavirus disease 2019 (COVID-19)-associated hospitalization surveillance network (COVID-NET)","volume":"72","author":"Kim","year":"2021","journal-title":"Clin Infect Dis."},{"key":"ref40","doi-asserted-by":"publisher","first-page":"19","DOI":"10.15585\/mmwr.mm7101a4","article-title":"Risk factors for severe COVID-19 outcomes among persons aged >\/=18\u2009years who completed a primary COVID-19 vaccination series \u2013 465 health care facilities, United States, December 2020-October 2021","volume":"71","author":"Yek","year":"2022","journal-title":"MMWR Morb Mortal Wkly Rep."},{"key":"ref41","doi-asserted-by":"publisher","first-page":"E66","DOI":"10.5888\/pcd18.210123","article-title":"Underlying medical conditions and severe illness among 540,667 adults hospitalized with COVID-19, March 2020\u2013March 2021","volume":"18","author":"Kompaniyets","year":"2021","journal-title":"Prev Chronic Dis."},{"key":"ref42","volume-title":"Science Brief: Evidence Used to Update the List of Underlying Medical Conditions Associated with Higher Risk for Severe COVID-19. CDC COVID-19 Science Briefs","year":"2020"},{"key":"ref43","doi-asserted-by":"publisher","first-page":"1068","DOI":"10.1016\/j.cmet.2020.04.021","article-title":"Association of blood glucose control and outcomes in patients with COVID-19 and pre-existing type 2 diabetes","volume":"31","author":"Zhu","year":"2020","journal-title":"Cell Metab."},{"key":"ref44","doi-asserted-by":"publisher","first-page":"e4113","DOI":"10.1093\/cid\/ciaa1787","article-title":"Impact of sex and metabolic comorbidities on coronavirus disease 2019 (COVID-19) mortality risk across age groups: 66 646 inpatients across 613 U.S","volume":"73","author":"Goodman","year":"2021","journal-title":"Hospitals Clin Infect Dis."},{"key":"ref45","doi-asserted-by":"publisher","first-page":"105941","DOI":"10.1016\/j.rmed.2020.105941","article-title":"Chronic obstructive pulmonary disease is associated with severe coronavirus disease 2019 (COVID-19)","volume":"167","author":"Lippi","year":"2020","journal-title":"Respir Med."},{"key":"ref46","doi-asserted-by":"publisher","first-page":"136","DOI":"10.1016\/j.atherosclerosis.2021.03.041","article-title":"Impact of clinical and subclinical coronary artery disease as assessed by coronary artery calcium in COVID-19","volume":"328","author":"Scoccia","year":"2021","journal-title":"Atherosclerosis"},{"key":"ref47","doi-asserted-by":"publisher","first-page":"2468","DOI":"10.1016\/j.jcmg.2020.07.004","article-title":"Coronary artery calcification and complications in patients with COVID-19","volume":"13","author":"Dillinger","year":"2020","journal-title":"JACC Cardiovasc Imaging"},{"key":"ref48","doi-asserted-by":"publisher","first-page":"717","DOI":"10.1016\/j.diii.2021.06.007","article-title":"Association between coronary artery calcifications and 6-month mortality in hospitalized patients with COVID-19","volume":"102","author":"Mousseaux","year":"2021","journal-title":"Diagn Interv Imaging"},{"key":"ref49","doi-asserted-by":"publisher","first-page":"204800402110593","DOI":"10.1177\/20480040211059374","article-title":"Cardiovascular health and risk of hospitalization with COVID-19: a Mendelian randomization study","volume":"10","author":"Cecelja","year":"2021","journal-title":"JRSM Cardiovasc Dis."},{"key":"ref50","doi-asserted-by":"publisher","first-page":"359","DOI":"10.1097\/MCA.0000000000000914","article-title":"Prognostic significance of cardiac injury in COVID-19 patients with and without coronary artery disease","volume":"32","author":"Barman","year":"2021","journal-title":"Coron Artery Dis."},{"key":"ref51","doi-asserted-by":"publisher","first-page":"669","DOI":"10.3390\/diagnostics10090669","article-title":"Sensitivity, specificity and predictive values of molecular and serological tests for COVID-19: a longitudinal study in emergency room","volume":"10","author":"Bisoffi","year":"2020","journal-title":"Diagnostics"}],"container-title":["Frontiers in Medicine"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmed.2023.1079165\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,2,8]],"date-time":"2023-02-08T16:53:52Z","timestamp":1675875232000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmed.2023.1079165\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,2,8]]},"references-count":51,"alternative-id":["10.3389\/fmed.2023.1079165"],"URL":"https:\/\/doi.org\/10.3389\/fmed.2023.1079165","relation":{},"ISSN":["2296-858X"],"issn-type":[{"value":"2296-858X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,2,8]]},"article-number":"1079165"}}