Immunological aspects of COVID-19 in children

Abstract

The authors present a review of the literature on the peculiarities of immunity in children, which may explain the differences in the symptoms of COVID-19 in childhood. In children, COVID-19 tends to occur more easily than in adults. However, as in the years of the pandemic, and in the post-pandemic period, there were quite a few cases of complicated course with the need for hospitalization, and sometimes with fatal outcomes. Infants under the age of 1 year account for the highest percentage of hospitalizations among children. Currently, the analysis of the results of comparing the clinical manifestations of the disease and laboratory data is continuing. Basically, the features of COVID-19 in children are explained by the immaturity of the immune system and the atrial fibrillation of the respiratory tract. It is known that in childhood there are fewer angiotensin converting enzyme type 2 receptors (ACE 2, ACE 2), with which the coronavirus enters the human body. The disease caused by SARS-CoV-2 in children is often accompanied by gastrointestinal manifestations. A small percentage of sick children may develop an intense inflammatory reaction called “multisystem inflammatory syndrome”, also known as MIS-C. In this condition, high titers of antibodies to RBD SARS-CoV-2 and autoantibodies to free interleukin (IL) -1Ra are detected. These data should be taken into account when clarifying the prevention and treatment regimens aimed at preventing complications in the pediatric population.