Researchers report strong pathogen interactions and a surge in Mycoplasma pneumoniae among children after restrictions were lifted
BEIJING, Feb. 12, 2026 /PRNewswire/ — Acute respiratory infections remain one of the leading causes of hospitalization in children worldwide. Pathogens may interact with one another, altering disease patterns in unpredictable ways. The COVID-19 pandemic, along with widespread mask use, school closures, and reduced social contact, created an unprecedented context for understanding these complex interactions.
In this vein, researchers from China examined data from 73,096 pediatric patients hospitalized with acute respiratory tract infections in Wenzhou and Ningbo, two eastern China cities with similar climates. The study led by Dr. Hailin Zhang and Dr. Shunhang Wen from The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, China, was published on 19 January, 2026 in Pediatric Investigation.
“This was a rare opportunity to observe how respiratory pathogens behaved and influenced one another, when their normal transmission patterns are disrupted and then suddenly restored,” says Dr. Zhang.
The team retrospectively analyzed respiratory samples collected between March 2021 and February 2024, encompassing periods before, during, and after the implementation of major COVID-19 control measures. Using a multiplex PCR test, they screened each sample for 13 non-bacterial respiratory pathogens, including influenza viruses, respiratory syncytial virus, rhinovirus, human coronaviruses, and Mycoplasma pneumoniae. Advanced statistical models were then used to examine co-infections and pathogen interactions over time. During strict non-pharmaceutical interventions, the overall detection rate of respiratory pathogens dropped by more than 56%, underscoring the effectiveness of COVID-19-related restrictions in suppressing transmission. However, once restrictions were revoked, detection rates rebounded by over 75%, with some pathogens exceeding the pre-pandemic levels.
The most striking increase involved Mycoplasma pneumoniae, an atypical bacterium commonly causing pneumonia in children. Its detection rate surged from 5.29% during the pandemic to 34.78% afterward, making it the most frequently detected pathogen in the post-pandemic period. “We were surprised by how sharply Mycoplasma pneumoniae rebounded. This suggests that a large pool of susceptible children was created during the pandemic, ” explains Dr. Wen.
After the pandemic, negative correlations between pathogens became stronger; the presence of one pathogen was associated with reduced detection rates of another.
One consistent finding was a negative/inverse relationship between the Influenza B virus and Mycoplasma pneumoniae, suggesting a phenomenon known as pathogen interference. “This pattern hints that infection with one pathogen may briefly suppress another, possibly through immune responses like interferon release,” Dr. Wen explained. “Understanding these dynamics could help clinicians anticipate shifts during outbreaks.”
Despite certain limitations, this study highlights the importance of ongoing post-COVID-19 surveillance. “In the post-pandemic era, respiratory pathogens are interacting in new ways, and public health systems need to be prepared for unexpected patterns of childhood infections,” Dr. Zhang concludes.
Overall, future prevention strategies including vaccinations and outbreak preparedness, should consider individual pathogens and their interactions within pediatric populations.
Reference
Title: Interaction analysis of non-bacterial respiratory pathogens during and after the coronavirus disease 2019 pandemic in two cities along the eastern coast of China
Journal: Pediatric Investigation
DOI: 10.1002/ped4.70034
Author names: Wanxian Ye, Jishan Zheng, Yungang Yang, Xinyue Song, Xiang Yuan, Lan Yang, Jian Yu, Hailin Zhang, and Shunhang Wen
About Wenzhou Medical University
Wenzhou Medical University (WMU) is a higher education institution under the Zhejiang Provincial Government administration. In 2015, WMU was shortlisted as a university jointly developed by the People’s Government of Zhejiang Province, the National Health Commission, and the Ministry of Education.
Website: https://en.wmu.edu.cn/
Contact:
Lu Lu
86-10-66019629
409078@email4pr.com
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SOURCE Pediatric Investigation
