[Clinical features of children with coronavirus disease 2019 caused by Delta variant infection in different age groups].

Objectives: To study the clinical features of children with coronavirus disease 2019 (COVID-19) caused by Delta variant infection in different ages groups.

Methods: A total of 45 children with COVID-19 caused by Delta variant infection who were hospitalized in the designated hospital in Henan Province, China, from November 17 to December 17, 2021, were included. They were divided into three groups: <6 years group ( n =16), 6-13 years group ( n =16), and >13 years group ( n =13). The three groups were compared in clinical features and laboratory examination data.

Results: COVID-19 in all age groups was mainly mild. Main manifestations included cough and expectoration in the three groups, and fever was only observed in the 6-13 years group. The <6 years group had significantly higher serum levels of aspartate aminotransferase, lactate dehydrogenase, and creatine kinase isoenzymes than the other two groups ( P <0.05). The 6-13 years group had the highest proportion of children with elevated serum creatinine levels (50%). Among the three groups, only 4 children in the >13 years group had an increase in serum C-reactive protein levels. The 6-13 years group had the lowest counts of CD3 + CD4 + lymphocytes, CD3 + CD8 + lymphocytes, and natural killer cells in the peripheral blood among the three groups. The >13 years group had a significantly higher positive rate of SARS-CoV-2 IgG on admission than the other two groups ( P <0.05). There was no significant difference in the imaging findings on chest CT among the three groups ( P >0.05).

Conclusions: The clinical features of COVID-19 caused by Delta variant infection in children of different age groups may be different: children aged <6 years tend to develop myocardial injury, and those aged 6-13 years have fever except cough and expectoration and tend to develop renal and immune dysfunction.