{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T06:05:20Z","timestamp":1780380320634,"version":"3.54.1"},"reference-count":34,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T00:00:00Z","timestamp":1780358400000},"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. Public Health"],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Identify risk factors for severe influenza in children under 5\u202fyears of age in the Fuzhou region to provide evidence-based support for early identification of high-risk patients, optimization of Pediatric Intensive Care Unit (PICU) resource allocation, and development of targeted intervention strategies.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>A total of 386 severe influenza cases and 1,544 non-severe cases among children under 5\u202fyears old in Fuzhou City were collected from January 2015 to January 2025. The non-severe cases were matched for the same period, same region, parental education level, and age (\u00b11\u202fyear). A retrospective case\u2013control study design was employed to analyze demographic characteristics, clinical symptoms, laboratory indicators, medical history, and viral subtypes between the two groups. Multivariate logistic regression analysis was used to identify independent risk factors for severe influenza.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Multivariate analysis revealed that male gender, children living in dispersed communities, obesity, rural residence, lack of influenza vaccination, time from onset to presentation &amp;gt;2\u202fdays, time from onset to antiviral treatment &amp;gt;2\u202fdays, persistent high fever &amp;gt;3\u202fdays, tachypnea\/dyspnea, altered mental status\/ convulsions, elevated neutrophil-to-lymphocyte ratio (NLR), high C-reactive protein (CRP) levels, low albumin levels, history of chronic respiratory disease, history of metabolic and endocrine disorders, and infection with influenza A (H1N1) virus were all risk factors for severe influenza in children under 5\u202fyears of age (all\n                      <jats:italic>p<\/jats:italic>\n                      \u202f&amp;lt;\u202f0.05). The median recovery time in the severe group was 19\u202fdays, significantly longer than the 10\u202fdays in the non-severe group (\n                      <jats:italic>p<\/jats:italic>\n                      \u202f&amp;lt;\u202f0.001).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>The occurrence of severe influenza in children under 5\u202fyears of age is influenced by multiple factors, including demographic characteristics, clinical features, laboratory indicators, past medical history, and viral subtype. Efforts should focus on strengthening prevention and control in key populations, increasing vaccination rates, optimizing the allocation of medical resources, and enhancing primary care capabilities to reduce the incidence of severe influenza in children and improve outcomes.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fpubh.2026.1718973","type":"journal-article","created":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T05:43:32Z","timestamp":1780379012000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Impact of demographic, clinical, and viral factors on severe influenza in young children in Fuzhou"],"prefix":"10.3389","volume":"14","author":[{"given":"Xiaoyan","family":"Zheng","sequence":"first","affiliation":[{"name":"The Affiliated Fuzhou Center for Disease Control and Prevention of Fujian Medical University","place":["Fuzhou, China"]},{"name":"The School of Public Health, Fujian Medical University","place":["Fuzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ling","family":"Yao","sequence":"additional","affiliation":[{"name":"Fujian Medical Uvniversity","place":["Fuzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhijie","family":"Wu","sequence":"additional","affiliation":[{"name":"Fujian Medical Uvniversity","place":["Fuzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaoyang","family":"Zhang","sequence":"additional","affiliation":[{"name":"The Affiliated Fuzhou Center for Disease Control and Prevention of Fujian Medical University","place":["Fuzhou, China"]},{"name":"The School of Public Health, Fujian Medical University","place":["Fuzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Youqiong","family":"Xu","sequence":"additional","affiliation":[{"name":"The Affiliated Fuzhou Center for Disease Control and Prevention of Fujian Medical University","place":["Fuzhou, China"]},{"name":"The School of Public Health, Fujian Medical University","place":["Fuzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,6,2]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"1418499","DOI":"10.3389\/fped.2024.1418499","article-title":"Clinical characteristics of severe influenza as a risk factor for febrile seizures in children: a retrospective analysis","volume":"12","author":"Li","year":"2024","journal-title":"Front Pediatr"},{"key":"ref2","doi-asserted-by":"publisher","first-page":"964","DOI":"10.1186\/s12879-019-4592-0","article-title":"Spectrum of clinical and radiographic findings in patients with diagnosis of H1N1 and correlation with clinical severity","volume":"19","author":"Schoen","year":"2019","journal-title":"BMC Infect Dis"},{"key":"ref3","doi-asserted-by":"publisher","first-page":"2179452","DOI":"10.1080\/22423982.2023.2179452","article-title":"Age-specific mortality and the role of living remotely: the 1918-20 influenza pandemic in Kautokeino and Karasjok, Norway","volume":"82","author":"Nygaard","year":"2023","journal-title":"Int J Circumpolar Health"},{"key":"ref4","doi-asserted-by":"publisher","first-page":"265","DOI":"10.1007\/s00431-013-2023-6","article-title":"The burden of seasonal and pandemic influenza in infants and children","volume":"173","author":"Ruf","year":"2014","journal-title":"Eur J Pediatr"},{"key":"ref5","doi-asserted-by":"publisher","first-page":"e143","DOI":"10.3346\/jkms.2019.34.e143","article-title":"Acute necrotizing encephalopathy in children: a long way to go","volume":"34","author":"Lee","year":"2019","journal-title":"J Korean Med Sci"},{"key":"ref6","doi-asserted-by":"publisher","first-page":"575","DOI":"10.1002\/jmv.27400","article-title":"Severe influenza virus infection in children admitted to the PICU: comparison of influenza a and influenza B virus infection","volume":"94","author":"Yazici \u00d6zkaya","year":"2022","journal-title":"J Med Virol"},{"key":"ref7","doi-asserted-by":"publisher","first-page":"961","DOI":"10.1080\/14787210.2016.1227701","article-title":"Severe influenza in children: incidence and risk factors","volume":"14","author":"Principi","year":"2016","journal-title":"Expert Rev Anti-Infect Ther"},{"key":"ref8","doi-asserted-by":"publisher","first-page":"e0273837","DOI":"10.1371\/journal.pone.0273837","article-title":"Hospital admissions with influenza and impact of age and comorbidities on severe clinical outcomes in Brazil and Mexico","volume":"17","author":"El Guerche-S\u00e9blain","year":"2022","journal-title":"PLoS One"},{"key":"ref9","doi-asserted-by":"publisher","first-page":"6623","DOI":"10.4048\/jimmunol.180.10.6623","article-title":"Cigarette smoke exposure impairs dendritic cell maturation and T cell proliferation in thoracic lymph nodes of mice","volume":"180","author":"Robbins","year":"2008","journal-title":"J Immunol"},{"key":"ref10","first-page":"95","article-title":"Clinical features of influenza A and B in children and association with myositis","volume":"37","author":"Hu","year":"2004","journal-title":"J Microbiol Immunol Infect"},{"key":"ref11","doi-asserted-by":"publisher","first-page":"1598","DOI":"10.1038\/s41564-020-00813-8","article-title":"Longitudinal observation and decline of neutralizing antibody responses in the three months following SARS-CoV-2 infection in humans","volume":"5","author":"Seow","year":"2024","journal-title":"Nat Microbiol"},{"key":"ref12","doi-asserted-by":"publisher","first-page":"17028","DOI":"10.1038\/s41598-022-21312-2","article-title":"The spatial-temporal distribution and etiological characteristics of hand-foot-and-mouth disease before and after EV\u2011A71 vaccination in Kunming, China, 2017-2020","volume":"12","author":"Wang","year":"2022","journal-title":"Sci Rep"},{"key":"ref13","doi-asserted-by":"publisher","first-page":"864","DOI":"10.3760\/cma.j.cn112140-20250228-00160","article-title":"Clinical characteristics of severe human metapneumovirus infection in children and analysis of risk factors for critical illness","volume":"63","author":"Liu","year":"2025","journal-title":"Zhonghua Er Ke Za Zhi"},{"key":"ref14","doi-asserted-by":"publisher","first-page":"1230","DOI":"10.1164\/rccm.201506-1122OC","article-title":"Impairment of immunoproteasome function by cigarette smoke and in chronic obstructive pulmonary disease","volume":"193","author":"Kammerl","year":"2024","journal-title":"Am J Respir Crit Care Med"},{"key":"ref15","doi-asserted-by":"publisher","first-page":"2437246","DOI":"10.1080\/22221751.2024.2437246","article-title":"Nationwide seroprevalence of SARS-CoV-2 Delta variant and five Omicron sublineages in companion cats and dogs in the USA: insights into their role in COVID-19 epidemiology","volume":"14","author":"Brits","year":"2025","journal-title":"Emerg Microbes Infect"},{"key":"ref16","doi-asserted-by":"publisher","first-page":"842","DOI":"10.1038\/s41591-020-0901-9","article-title":"Single-cell landscape of bronchoalveolar immune cells in patients with COVID-19","volume":"26","author":"Liao","year":"2024","journal-title":"Nat Med"},{"key":"ref17","doi-asserted-by":"publisher","first-page":"1700732","DOI":"10.2807\/1560-7917.ES.2018.23.43.1700732","article-title":"Influenza vaccine effectiveness in reducing severe outcomes over six influenza seasons, a case-case analysis, Spain, 2010\/11 to 2015\/16","volume":"23","author":"Godoy","year":"2018","journal-title":"Euro Surveill"},{"key":"ref18","doi-asserted-by":"publisher","first-page":"11","DOI":"10.2165\/00044011-200323010-00002","article-title":"Influenza diagnosis and treatment","volume":"23","author":"Sch\u00e4tz","year":"2003","journal-title":"Clin Drug Investig"},{"key":"ref19","doi-asserted-by":"publisher","first-page":"183","DOI":"10.1016\/B978-0-12-800869-0.00007-X","article-title":"Surveillance and response strategy in the malaria post-elimination stage: case study of Fujian province","volume":"86","author":"Yang","year":"2014","journal-title":"Adv Parasitol"},{"key":"ref20","doi-asserted-by":"publisher","first-page":"864","DOI":"10.1016\/j.immuni.2020.07.026","article-title":"Acute SARS-CoV-2 Infection Impairs Dendritic Cell and T Cell Responses","volume":"53","author":"Zhou","year":"2020","journal-title":"Immunity"},{"key":"ref21","doi-asserted-by":"publisher","first-page":"848","DOI":"10.1111\/jpc.15857","article-title":"Risk factors and disease severity in Australian infants aged under 6 months hospitalised with influenza 2011-2019","volume":"58","author":"McRae","year":"2022","journal-title":"J Paediatr Child Health"},{"key":"ref22","doi-asserted-by":"publisher","first-page":"1309","DOI":"10.1111\/j.1530-0277.2008.00699.x","article-title":"Effects of chronic ethanol feeding on murine dendritic cell numbers, turnover rate, and dendropoiesis","volume":"32","author":"Edsen-Moore","year":"2008","journal-title":"Alcohol Clin Exp Res"},{"key":"ref23","doi-asserted-by":"publisher","first-page":"1","DOI":"10.12998\/wjcc.v10.i1.1","article-title":"Omicron variant (B.1.1.529) of SARS-CoV-2: Mutation, infectivity, transmission, and vaccine resistance","volume":"10","author":"Ren","year":"2022","journal-title":"World J Clin Cases"},{"key":"ref24","doi-asserted-by":"publisher","first-page":"32","DOI":"10.1016\/j.jpeds.2021.06.075","article-title":"Prevalence, risk factors, and outcomes of influenza-associated neurologic complications in children","volume":"239","author":"Antoon","year":"2021","journal-title":"J Pediatr"},{"key":"ref25","doi-asserted-by":"publisher","first-page":"127","DOI":"10.3390\/idr17050127","article-title":"The neutrophil\/lymphocyte ratio was identified as a marker of severe influenza during the 2024-2025 outbreak in France","volume":"17","author":"Vassallo","year":"2025","journal-title":"Infect Dis Rep"},{"key":"ref26","doi-asserted-by":"publisher","first-page":"39","DOI":"10.1007\/s00011-018-1188-x","article-title":"C-reactive protein as a biomarker of severe H1N1 influenza","volume":"68","author":"Vasileva","year":"2019","journal-title":"Inflamm Res"},{"key":"ref27","doi-asserted-by":"publisher","first-page":"200","DOI":"10.3969\/j.issn.1673-5501.2024.03.007","article-title":"Risk factors for severe influenza A in children: A case-control study","volume":"19","author":"Xie","year":"2024","journal-title":"Chin J Evid Based Pediatr"},{"key":"ref28","doi-asserted-by":"publisher","first-page":"372","DOI":"10.1038\/nri803","article-title":"Effects of cigarette smoke on the immune system","volume":"2","author":"Sopori","year":"2024","journal-title":"Nat Rev Immunol"},{"key":"ref29","doi-asserted-by":"publisher","first-page":"879","DOI":"10.7326\/M20-2671","article-title":"Contact settings and risk for transmission in 3410 close contacts of patients with COVID-19 in Guangzhou, China : a prospective cohort study","volume":"173","author":"Luo","year":"2020","journal-title":"Ann Intern Med"},{"key":"ref30","doi-asserted-by":"publisher","first-page":"1004","DOI":"10.1016\/S1473-3099(20)30433-3","article-title":"Assessment of patients who tested positive for COVID-19 after recovery","volume":"20","author":"Mei","year":"2024","journal-title":"Lancet Infect Dis"},{"key":"ref31","doi-asserted-by":"publisher","first-page":"874","DOI":"10.1016\/j.ijid.2022.07.050","article-title":"Safety and immunogenicity of inactivated SARS-CoV-2 vaccines in people with gastrointestinal cancer","volume":"122","author":"Li","year":"2022","journal-title":"Int J Infect Dis"},{"key":"ref32","doi-asserted-by":"publisher","first-page":"168","DOI":"10.15585\/mmwr.mm7308a3","article-title":"Interim estimates of 2023\u201324 seasonal influenza vaccine effectiveness - United States","volume":"73","author":"Frutos","year":"2024","journal-title":"MMWR Morb Mortal Wkly Rep"},{"key":"ref33","doi-asserted-by":"publisher","first-page":"e2023061545","DOI":"10.1542\/peds.2023-061545","article-title":"Vaccine mandates and influenza vaccination during the pandemic","volume":"152","author":"Abraham","year":"2023","journal-title":"Pediatrics"},{"key":"ref34","doi-asserted-by":"publisher","first-page":"e01136","DOI":"10.1002\/cti2.1136","article-title":"Detection of IgM and IgG antibodies in patients with coronavirus disease 2019","volume":"9","author":"Hou","year":"2020","journal-title":"Clin Transl Immunol"}],"container-title":["Frontiers in Public Health"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fpubh.2026.1718973\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T05:43:35Z","timestamp":1780379015000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fpubh.2026.1718973\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,2]]},"references-count":34,"alternative-id":["10.3389\/fpubh.2026.1718973"],"URL":"https:\/\/doi.org\/10.3389\/fpubh.2026.1718973","relation":{},"ISSN":["2296-2565"],"issn-type":[{"value":"2296-2565","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,2]]},"article-number":"1718973"}}