Covid-19 in Children: Summarizing Worldwide Experience to Date

Abstract

The purpose of this bibliographical review is to provide an exceptional and up-to-date overview of COVID-19 infection in children describing its epidemiology, pathogenesis, clinical features and outcomes. The article provides a comprehensive analysis of publications by foreign and Russian authors on a new coronavirus infection (COVID-19) caused by SARS-CoV-2 in children. A complete clinical description of the course of COVID-19 in pediatric population is given: from asymptomatic virus carrying till the development of acute pneumonia, multi-inflammatory syndrome, multiple organ failure and death. Among the clinical manifestations there are described as follows: respiratory syndrome, gastrointestinal tract injury, manifestations in the central nervous system, lesions of the skin and mucous membranes and a complete characteristic of multi-inflammatory syndrome. The studied methods of development of COVID-19 are examined in pathogenesis. The issues of anti-tuberculosis vaccination, the impact of serum cholecalciferol level on the severity and outcomes of COVID-19 disease are highlighted. The latest publications on intrauterine infection of the fetus and the breast milk research for the presence of SARS-CoV-2 were analyzed.

COVID-19 Heart Lesions in Children: Clinical, Diagnostic and Immunological Changes

“…In the beginning of COVID-19, the proportion of confirmed cases in the pediatric population was relatively small and there was an opinion that children had often the mild or asymptomatic course of infection [ 23 , 24 , 25 , 26 ]. According to the literature, incidence of novel coronavirus infection in the pediatric population is relatively low compared to adults and ranges from 1% to 16% [ 27 , 28 , 29 ]. In most children with COVID-19, the disease is mild, moreover, asymptomatic infection is registered in 15–42% of children [ 30 ].…”

“…In most children with COVID-19, the disease is mild, moreover, asymptomatic infection is registered in 15–42% of children [ 30 ]. Mild COVID-19 in childhood lead some authors to explain the absence of population decreasing T and B lymphocytes [ 27 , 31 ]. Other authors have suggested a protective role prevention of tuberculosis [ 32 ].…”

“…It should be noted that in some case series, there is a high proportion of African American patients and Latin American as well [ 42 ]. According to some data, MIS-C develops in genetically predisposed individuals due to a hyperinflammatory reaction after COVID-19 and affects several organs, including the cardiovascular system [ 27 ]. It was observed hypotension and shock (20–100%) in some patients or as a result of severe myocardial dysfunction or as a result of systemic hyperinflammation or vasodilation.…”

“…A number of studies have shown that myocarditis, associated with MIS-C, proceeds more easily than myocarditis in adults against the background of SARS-CoV-2 [ 67 ]. Patients had a mild increase of troponin and then a rapid restoration of the LV function against the therapy background [ 27 , 37 , 64 , 68 ]. Nevertheless, there is evidence that diastolic dysfunction can last for 6 months after an acute disease in some patients [ 63 ].…”

Severe Course of COVID-19 and Long-COVID-19 in Children: Difficulties in Diagnosis

“…There is an interesting fact that MIS-C can develop in patients with asymptomatic COVID-19 and patients with severe disease [ 22 , 23 , 24 , 25 ]. It is not clear which factors are predisposing to the development of MIS-C after COVID-19, as well as examination methods that should be used for the diagnosis of MIS-C [ 26 , 27 ].…”