Abstract
BACKGROUND: Acute respiratory tract infections (ARTIs) are a major cause of morbidity and hospitalization in pediatric populations. The COVID-19 pandemic has led to significant shifts in the epidemiology of respiratory viruses, particularly influenza viruses and human bocavirus 1 (HBoV1). This study aims to investigate the impact of the pandemic on the prevalence of HBoV1 and its clinical implications in pediatric ARTIs. MATERIALS AND METHODS: A retrospective cohort study was conducted in a tertiary pediatric emergency department (ED) over three consecutive winter seasons: the pre-pandemic period (2017-2019) and the post-pandemic period (2022-2024). Nasopharyngeal swabs were analyzed using multiplex polymerase chain reaction (PCR) to identify respiratory viruses. Clinical and demographic characteristics, hospitalization rates, disease severity, and outcomes were systematically evaluated. RESULTS: Among 541 children (median age: 14 months), respiratory viruses were identified in 53.9%. The prevalence of HBoV1 increased significantly in the post-pandemic period (9.5% vs. 20.8%)(p < 0.001), whereas influenza A/B infections declined (p < 0.001). Co-infections decreased (13.4% to 5.3%), though HBoV1 was strongly linked to co-infections (p = 0.001). Severe illness was significantly associated with co-infections (aOR: 7.3, 95% CI: 3.9-14.2, p < 0.001) and age ≤ 1 year (aOR: 2.6, 95% CI: 1.2-5.1, p = 0.008). CONCLUSION: The post-pandemic period is characterized by an increased prevalence of HBoV1 and a decline in influenza A/B infections. While HBoV1 alone does not appear to contribute to severe disease, co-infections, particularly with RSV, significantly increase morbidity. These findings highlight the need for continued viral surveillance and tailored clinical management strategies to address shifting epidemiological patterns in pediatric ARTIs. CLINICAL TRIAL: Not applicable.