Comparative characteristics of the clinical picture of COVID-19 in children in 2020 and 2021

Background: In Ukraine there have been two periods of increased incidence of COVID-19 in 2020 and 2021. The pandemic has wavy character, which may be due, to the high mutational activity, which leads to the rapid formation of new variants of the virus. Materials and Methods: There was an analysis of 530 case histories of children from birth to 18 years old, who were hospitalized with coronavirus disease in the period from June 2020 to May 2021. Results: In 2021 the share of children aged 1 to 5 increased significantly (from 26.2% to 41%) and the percentage of adolescent visitors decreased (from 24.7% to 15.8%). We found that the average number of patients in 2021 increased in some children with chronic controversial pathology (14.7% in 2021 and 5% in 2020). In 2021, the part with general symptoms and local manifestations of airway lesions significantly increased (p<0.05) 81.15% in 2020). During the wave of 2021, 18 (9.5%) children were involved in intensive care units and the average in 2020 only 7 (2%). Conclusions: During the second wave of coronavirus infection in Ukraine, we observed an increase in the proportion of young and preschool children among inpatients. In the clinical picture of the disease of patients during the second wave of of COVID-19, we observed an increase in the absolute number and proportion of children with severe and complicated forms of the disease.