Analysis of pediatric respiratory virus epidemiology and its association with atmospheric parameters in Chengdu

The relaxation of non-pharmaceutical interventions (NPIs) following the coronavirus disease 2019 (COVID-19) pandemic has altered the global epidemiology of respiratory viruses. This study aimed to characterize the epidemiological patterns of common respiratory viruses among hospitalized children in Chengdu, China, and to explore their potential associations with local atmospheric parameters.

Retrospective analysis of clinical data from children with acute respiratory infections (ARIs) admitted to Chengdu Women's and Children's Central Hospital between January 2023 and December 2024. Detection was performed on pharyngeal swab samples using multiplex real-time polymerase chain reaction (PCR), targeting human rhinovirus (HRV), human adenovirus (HADV), human respiratory syncytial virus (HRSV), influenza A virus (InfA), and influenza B virus (InfB). Concurrently, monthly average atmospheric data-including temperature, relative humidity, Air Quality Index (AQI), particulate matter (PM_2.5, PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), carbon monoxide (CO), and ozone (O₃)-were obtained for Chengdu. Statistical analyses utilized Chi-squared tests for epidemiological comparisons and Pearson correlation alongside linear regression to assess virus-atmosphere relationships.

Among 322,238 children tested, 30,523 (9.47%) were positive for at least one target virus. HRV was the most prevalent pathogen (3.84%), followed by HADV (2.49%), HRSV (1.86%), InfA (0.90%), and InfB (0.38%). Male infection rates were significantly higher than those of females (ratio 1.32:1, P<0.01) and highest in preschool-aged children (10.58%). A distinct seasonal variation was observed, with the highest overall positivity rate occurring in winter (10.90%) and the lowest in summer (7.68%). HRSV, InfA, and InfB exhibited winter peaks, whereas HADV activity was highest in summer. HRSV infection was associated with the most severe clinical outcomes, including the highest rates of pediatric intensive care unit (PICU) admission (4.13%) and severe pneumonia (5.79%). Significant correlations were identified between atmospheric factors and virus detection rates: monthly temperature correlated negatively with HRSV (r=-0.412, P<0.05), InfB (r=-0.516, P<0.01), and InfA (r=-0.551, P<0.01) but positively with HADV (r=0.441, P<0.05). Several air pollutants, including PM_2.5, PM₁₀, and NO₂, were also significantly associated with the activity of specific viruses.

These findings offer valuable insights into the localized epidemiology of pediatric respiratory viruses and their associations with atmospheric factors in Chengdu, providing a reference for the development of regional prevention strategies and individualized child health protection measures.