Objective:

To describe changes in pediatric respiratory pathogen detection patterns in Guangzhou, focusing on a season-matched comparison before and after the lifting of COVID-19 restrictions.

Approach:

• Study Design: Retrospective analysis of 2,213 children aged 0 to <16 years presenting with fever or respiratory symptoms at Guangzhou Women and Children's Medical Center.
• Data Collection: Nasopharyngeal swabs were collected and tested using a 12-pathogen multiplex PCR panel during two periods: pre-lifting (November 2021–October 2022) and post-lifting (February–May 2023).
• Statistical Analysis: Categorical variables were compared using Chi-square test or Fisher's exact test, focusing on February–May 2022 vs. February–May 2023 to reduce seasonal bias.

Key Findings:

• 38.1% of children tested positive for at least one pathogen.
• Increased detection rates of Influenza A (0.64% vs. 16.60%), RSV (5.72% vs. 14.67%), and HRV (1.06% vs. 5.79%) in February–May 2023 compared to February–May 2022.
• Decreased detection rates of Influenza B (7.84% vs. 0.39%) and HMPV (10.59% vs. 0.39%) in the same comparison.
• Post-lifting cohort had a higher proportion of infants (<1 year: 14.29% vs. 8.50%) and more lower respiratory tract diagnoses.

Interpretation:

The findings indicate a shift in pediatric respiratory pathogen detection towards increased activity of certain viruses following the lifting of COVID-19 restrictions, with changes in patient demographics and clinical presentations.

Limitations:

• Causal attribution to the lifting of restrictions should be made cautiously due to potential confounding factors such as seasonality, SARS-CoV-2 circulation, and changes in health-care-seeking behavior.

Conclusion:

The study highlights the need for continued multiplex surveillance and age-targeted prevention strategies in pediatric populations.