Assessing the change in the epidemiology of seasonal respiratory viruses with the onset of the COVID-19 pandemic.

Background. Respiratory tract infections are among the most important causes of mortality and morbidity in children worldwide. The COVID-19 pandemic has affected the distribution of seasonal respiratory viruses as in all areas of life. In this study, we have aimed to evaluate the changes in the rates of seasonal respiratory viruses with the onset of the pandemic.Methods. This study included patients who were admitted to the Pediatrics Clinic of Eskisehir Osmangazi University Faculty of Medicine Hospital between December 2018 and February 2022 with respiratory tract infections and in whom pathogens were detected from nasopharyngeal swab samples analysed by multiplex PCR method.Results. A total of 833 respiratory tract pathogens were detected in 684 cases consisting of male (55.3 %), and female (44.7 %), patients with a total mean age of 42 months. Single pathogen was revealed in 550, and multiple pathogens in 134 cases. Intensive care was needed in 14 % of the cases. Most frequently influenza A/B, rhinovirus and respiratory syncytial virus (RSV) were detected during the pre-pandemic period, while rhinovirus, RSV, and adenovirus were observed during the lockdown period. In the post-lockdown period, the incidence rates of rhinovirus, RSV, human bocavirus (HboV) (12 %), influenza virus infections increased, and patients with RSV and bocavirus infections required intensive care hospitalization.Conclusion. It is thought that the COVID-9 pandemic lockdown measures may have an impact on the distribution of seasonal respiratory viruses, especially RSV and influenza. Current, prospective and large case series regarding the mechanism of action and dynamics are needed.