Factors associated with severe COVID-19 among children aged <12 years in Fuzhou, China: a frequency-matched case-control study
Abstract
BackgroundEvidence on social, preventive, and clinical factors associated with severe pediatric COVID-19 remains limited in regional Chinese surveillance settings. We evaluated these factors among children aged <12 years in Fuzhou.MethodsWe conducted a frequency-matched case-control study of 347 severe cases and 694 non-severe controls identified from sentinel hospitals and the China Disease Prevention and Control Information System between January 2020 and August 2025. Controls were sampled at a 1:2 ratio by broad onset period, geographic sampling stratum, and parental education level. Group differences were assessed using Pearson's chi-square test. Given frequency matching without individual matched sets, unconditional multivariable logistic regression was used. Concurrent clinical manifestations were interpreted as warning indicators rather than antecedent etiologic risk factors.ResultsThe selected sample comprised 1,041 children (347 severe cases and 694 non-severe controls). Severe disease was positively associated with male sex (adjusted odds ratio [aOR] 1.897, 95% CI 1.451-2.481), age <=5 years (aOR 1.578, 95% CI 1.209-2.061), home-based/preschool care (aOR 2.771, 95% CI 2.033-3.776), rural residence (aOR 2.470, 95% CI 1.858-3.283), delayed consultation of >2 days (aOR 1.902, 95% CI 1.388-2.605), obesity (aOR 2.028, 95% CI 1.398-2.941), chronic respiratory disease (aOR 3.425, 95% CI 2.558-4.586), and metabolic or endocrine disease (aOR 3.928, 95% CI 2.826-5.460). Vaccination (aOR 0.537, 95% CI 0.363-0.793) and disease-prevention awareness (aOR 0.395, 95% CI 0.299-0.522) were inversely associated with severity. Fever lasting >3 days, dyspnea, and altered mental status were more frequent in severe cases and were treated as concurrent clinical warning indicators.ConclusionWithin this selected regional case-control sample, severe pediatric COVID-19 was associated with demographic, caregiving, healthcare-access, and pre-existing health factors. Vaccination and disease-prevention awareness were inversely associated with severity. The identified clinical manifestations serve as early-recognition and triage cues rather than baseline risk factors. Temporal and selection-related limitations warrant cautious generalization.
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BibTeX
@article{zheng2026factors,
title = {{Factors associated with severe COVID-19 among children aged <12 years in Fuzhou, China: a frequency-matched case-control study}},
author = {Xiaoyan Zheng and Ling Yao and Xi Chen and Xinyu Wang and Ruoyan Lu and Jinni Xu and Xiaoyang Zhang and Youqiong Xu},
journal = {Frontiers in Immunology},
year = {2026},
month = nov,
doi = {10.3389/fimmu.2026.1742196},
url = {https://www.frontiersin.org/articles/10.3389/fimmu.2026.1742196},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Factors associated with severe COVID-19 among children aged <12 years in Fuzhou, China: a frequency-matched case-control study
AU - Xiaoyan Zheng
AU - Ling Yao
AU - Xi Chen
AU - Xinyu Wang
AU - Ruoyan Lu
AU - Jinni Xu
AU - Xiaoyang Zhang
AU - Youqiong Xu
PY - 2026
DA - 2026/11/09
JO - Frontiers in Immunology
DO - 10.3389/fimmu.2026.1742196
UR - https://www.frontiersin.org/articles/10.3389/fimmu.2026.1742196
AB - BackgroundEvidence on social, preventive, and clinical factors associated with severe pediatric COVID-19 remains limited in regional Chinese surveillance settings. We evaluated these factors among children aged <12 years in Fuzhou.MethodsWe conducted a frequency-matched case-control study of 347 severe cases and 694 non-severe controls identified from sentinel hospitals and the China Disease Prevention and Control Information System between January 2020 and August 2025. Controls were sampled at a 1:2 ratio by broad onset period, geographic sampling stratum, and parental education level. Group differences were assessed using Pearson's chi-square test. Given frequency matching without individual matched sets, unconditional multivariable logistic regression was used. Concurrent clinical manifestations were interpreted as warning indicators rather than antecedent etiologic risk factors.ResultsThe selected sample comprised 1,041 children (347 severe cases and 694 non-severe controls). Severe disease was positively associated with male sex (adjusted odds ratio [aOR] 1.897, 95% CI 1.451-2.481), age <=5 years (aOR 1.578, 95% CI 1.209-2.061), home-based/preschool care (aOR 2.771, 95% CI 2.033-3.776), rural residence (aOR 2.470, 95% CI 1.858-3.283), delayed consultation of >2 days (aOR 1.902, 95% CI 1.388-2.605), obesity (aOR 2.028, 95% CI 1.398-2.941), chronic respiratory disease (aOR 3.425, 95% CI 2.558-4.586), and metabolic or endocrine disease (aOR 3.928, 95% CI 2.826-5.460). Vaccination (aOR 0.537, 95% CI 0.363-0.793) and disease-prevention awareness (aOR 0.395, 95% CI 0.299-0.522) were inversely associated with severity. Fever lasting >3 days, dyspnea, and altered mental status were more frequent in severe cases and were treated as concurrent clinical warning indicators.ConclusionWithin this selected regional case-control sample, severe pediatric COVID-19 was associated with demographic, caregiving, healthcare-access, and pre-existing health factors. Vaccination and disease-prevention awareness were inversely associated with severity. The identified clinical manifestations serve as early-recognition and triage cues rather than baseline risk factors. Temporal and selection-related limitations warrant cautious generalization.
SN - 1664-3224
ER -