ORIGINAL RESEARCH article
Front. Cell. Infect. Microbiol.
Sec. Virus and Host
This article is part of the Research TopicViral Pathogenesis and Host Defense: Understanding the Missing Links to Combat DiseaseView all 10 articles
Epidemiological and Immunological Insights into Respiratory Infections in Post-COVID-19
Provisionally accepted
Jie Yi1*
Ziyi Wang1
Yi Li1
Jianpiao CAI2
Yujie Sun1Mulatijiang Maimaiti1Yiwei Liu1Chenlin Yang1
Wenjing Liu1Sabrina Li3Yi Ren3Yu Chen1
Qiwen Yang1
Ying-Chun Xu1*- 1Peking Union Medical College Hospital (CAMS), Beijing, China
- 2The University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong, Hong Kong, SAR China
- 3Coyote Bioscience Research Institute, Beijing, China
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This is a provisional file, not the final typeset article Post-COVID-19 respiratory infection dynamics require updated epidemiological characterization to inform clinical surveillance and public health strategy. We analyzed 2484 patients with respiratory tract infections (September 2023–February 2024) using comprehensive pathogen screening (29 viral, bacterial, and atypical targets) and cytokine quantification (12 cytokines). Overall pathogen detection was 70.73%, with viral and bacterial identification in 40.42%(1004/2484), 51.45%(1278/2484) of cases respectively, and co-infections in 31.88% (predominantly Haemophilus influenzae-virus). Pediatric patients (<18 years) showed significantly higher positivity (74.1% vs. 63.2%, P<0.05) with viral predominance (41.57% vs. 37.84%), while adults showed bacterial predominance (57.38% vs. 38.23%). Pneumonia risk exhibited age-pathogen specificity: Mycoplasma pneumoniae posed the highest risk in children (41.1% pneumonia rate) versus influenza B in adults (10.2% detection rate). Retrospective cytokine analysis (pre-pandemic 2018–2019 vs. post-pandemic 2023–2024) revealed post-pandemic suppression of IL-6 (6.12 vs.3.82 pg/mL) and IL-8 (37.98 vs. 18.35 pg/mL), with resurgence in 2024, particularly in pediatric and pneumonia cases (P<0.05). Post-pandemic respiratory pathogen epidemiology is characterized by heightened pediatric susceptibility to viral co-infections, bacterial pathogen persistence despite control measures, and dysregulated inflammatory responses. These findings warrant age-stratified diagnostic and surveillance approaches with adaptive public health strategies to reduce respiratory infection morbidity.
Keywords: COVID-19, respiratory pathogens, Epidemiological feature, Coinfection, Immuneresponses
Received: 24 May 2025; Accepted: 05 Dec 2025.
Copyright: © 2025 Yi, Wang, Li, CAI, Sun, Maimaiti, Liu, Yang, Liu, Li, Ren, Chen, Yang and Xu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Jie Yi
Ying-Chun Xu
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