Shifting Patterns of Pediatric Respiratory Viruses During the SARS-CoV-2 Pandemic: A Retrospective Observational Study

Background: Respiratory tract infections are a leading cause of hospitalization in children and remain a significant contributor to pediatric morbidity. Understanding the epidemiology of viral pathogens—including their seasonal trends and response to global events like pandemics—is essential for public health planning, surveillance strategies, and timely clinical interventions. Methods: This retrospective study evaluated the epidemiology of respiratory viruses in pediatric patients before and during the SARS-CoV-2 pandemic. Nasopharyngeal swab samples from 1,269 children presenting with respiratory symptoms between October 2018 and September 2021 were tested using multiplex PCR targeting RV/EV, RSV A/B, seasonal coronaviruses, influenza, parainfluenza, hMPV, and other viruses. Results: 889 viruses were detected; 579 were single-virus infections, and 143 involved co-infections. RV/EV was the most frequently detected virus in all age groups. RSV was predominant in children under one year, while influenza was more common in older children. The highest testing volume and positivity rates occurred in January. The overall number of tests and positive detections decreased during the pandemic period. RSV, influenza, parainfluenza, and seasonal coronaviruses showed marked declines, whereas RV/EV frequency increased. Conclusions: The circulation of pediatric respiratory viruses shifted significantly during the pandemic. Multiplex PCR-based diagnostics proved valuable for tracking these changes, enabling rapid diagnosis and real-time epidemiological insight. These findings underscore the importance of molecular surveillance in managing pediatric respiratory infections, particularly during global health events.