CLINICAL AND EPIDEMIOLOGICAL FEATURES OF THE COURSE OF BRONCHIOLITIS OF RESPIRATORY SYNCYTIAL VIRКГЫ ETIOLOGY IN CHILDREN IN THE PRE-PANDEMIC PERIOD AND DURING THE DECLINE OF THE INCIDENCE OF COVID-19

Introduction. The appearance of the SARS-CoV-2 virus has led to a change in a number of manifestations of the epidemiological process for a group of acute respiratory virus infections, including respiratory syncytial virus infection. However, there is insufficient data on a possible change in the nature of the clinical course of respiratory syncytial virus infection during the period of COVID-19 circulation. The aim of the research: to study the clinical and epidemiological features of the course of bronchiolitis of respiratory syncytial virus etiology in children in the pre-pandemic period and during the decline of COVID-19 incidence. Materials and methods. A study of 332 cards of children hospitalized in the Regional Clinical Infectious Diseases Hospital (Chita, Zabaikalsky Krai) with a diagnosis of Acute bronchiolitis of respiratory syncytial virus etiology was conducted. 2 observation groups were identified: the first group of the pre–pandemic period – 207 patients (2013 to 2017), the second group during the period of decrease in COVID-19 incidence (2021–2023), n=125. Statistical data processing was carried out by the STATISTICA 6.1 software package. Results. The epidemic season of respiratory syncytial infection (RSVI) 2021–2022 was characterized by an early onset with peaks in incidence in December and February. The epidemic season of 2022-2023 was accompanied by a late start of hospitalization for RSVI in January 2023, with the maximum number of cases in March and April. Severe forms of bronchiolitis developed in 15,5% of cases in the first group and in 8,8% in the second. Patients who received treatment in the period 2013–2017 more often needed hospitalization in the intensive care unit and artificial lung ventilation, which may be explained by the more frequent development of complications (pneumonia) detected in this group. Conclusion. The circulation of the respiratory syncytial virus during the extinction of the COVID-19 pandemic remains almost at the inter-pandemic level. Regardless of the circulation of the SARS-CoV-2 virus among the population, the clinical picture of respiratory syncytial virus associated bronchiolitis in children has not changed. With a decrease in the incidence of bacterial complications (pneumonia) and the need for intensive care in the 2021–2023 season.