The etiological structure of severe acute respiratory viral infections in children in different epidemic seasons of the post-COVID period

Aim – studying the etiology of severe acute respiratory infections in the hospitalized children during the post-COVID period (2022 to 2024)

Materials and methods. 646 nasopharyngeal swabs from the patients admitted to pediatric hospitals of Ekaterinburg were tested using RT-PCR. The material was selected in compliance with the approved criteria and tested for the presence of viral pathogens influenza viruses A and B and a number of the respiratory viruses that make the conventional diagnostic panel). Results. 267 children were examined in the epidemic season of 2022 and 2023, and 379 children were examined in the epidemic season of 2023 and 2024. During the periods under analysis, the established viral etiology of SARIs accounted for over 60.0%. In 2022 and 2023, SARIs of the influenza etiology accounted for 52.2%, resulting from isolation of influenza virus А(H1N1)pdm09 and that of influenza virus B. Non-influenza etiology was characterized by identification of hRSv, hRhv and hBov. During the next season, respiratory viruses including hRSv, hRhv and hAdv, accounted for the most SARIs. Among the influenza viruses, influenza A (H3N2) accounted. Analysis of the combined isolation of multiple respiratory viruses from a single individual showed that in the season of 2023 and 2024, the frequency of mixed infection isolation more than doubled. Most of the coinfections were due to respiratory viruses.

Conclusion. Studying the etiologic agents of the respiratory infections whose symptoms required admittance of pediatric patients to hospital is significant, especially in the post-COVID period, as the pandemic spread of SARS-CoV-2 virus was characterized by suppressing circulation of respiratory viruses, namely, influenza viruses.