Genetic aspects of vulnerability to COVID-19 and their influence on individual susceptibility to severe disease in children

Despite the lower prevalence of COVID-19 (COronaVIrus Disease 2019) infection in children, such threatening conditions as severe SARS-CoV-2-associated pneumonia and Multisystem Inflammatory Syndrome in Children (MIS-C) pose a challenge in differential diagnosis, early hospitalization and treatment. Therefore, the purpose of the study was to investigate the genetic characteristics of children's susceptibility to the occurrence of severe COVID-19 and MIS-C, with the determination of predictors and risk factors. Genetic factors were evaluated on the basis of a literature search, and phenotypic manifestations were assessed on the basis of the analysis of medical documentation of 119 patients, who were treated in infectious departments with the diagnoses of COVID-19 (n=38), MIS-C (n=8), influenza (n=45), and acute viral respiratory infection (n=28). The results of the study revealed differential diagnostic criteria for severe forms of COVID-19 and MIS-C. Among COVID-19 symptoms, gastrointestinal manifestations prevailed, such as nausea, vomiting, diarrhea and abdominal pain. While rash, bilateral conjunctivitis, lymphadenopathy, gastrointestinal and cardiovascular disorders were chara­cteristic of MIS-C. Based on the analysis of genetic features, risk factors and co-morbidities that aggravate the course of covid infection have been determined in order to create algorithms for ambulatory supervision and dispensation of children from risk groups. Thus, children with asthma, diabetes, obesity, congenital immunodeficiencies and heart defects need dispensary supervision from the point of view of risk of severe COVID-19. Outpatient supervision for a month is required for practically healthy children who have had positive COVID-19 test or have been in contact with patients with COVID-19. The determination of blood laboratory parameters, electrocardiography and ultrasound of the abdominal organs should be performed for early diagnosis of MIS-C. Keywords: multisystem inflammatory syndrome MIS-C, severe form of COVID-19, risk factors, genetic features, dispensation, diagnostic criteria.