This study presents the results of treatment of 98 patients with risk of development of severe coronavirus disease (hereinafter COVID-19) with the first positive result of polymerase chain reaction test for SARS-CoV-2 in a day clinic of the multidisciplinary Z.A. Bashlyaeva Children’s Municipal Clinical Hospital. To prevent the clinical manifestation of COVID-19 and the progression of the main disease all these children were treated with virus-neutralizing monoclonal antibodies (sotrovimab 500 mg dissolved in 92 mL of 0.9% sodium chloride solution intravenously for 30 minutes, once, for children over 12 years old and with body weight over 12 kg; balanivimab 700 mg + etesivimab 1400 mg pre-dissolved in 250 mL of 0.9% sodium chloride solution intravenously for 30 minutes, once). Patients underwent a comprehensive clinical, laboratory and instrumental examination both initially and in dynamics for 3–7–11 days after therapy according to the developed clinical algorithm. The effectiveness of biological therapy in children with a risk of severe COVID-19 was noted in 100% of cases. None of the observed patients had either a clinical manifestation of COVID-19 or a relapse of the main chronic disease.