Abstract
<jats:p>Since the beginning of the COVID-19 pandemic, children were considered almost non-susceptible to the new virus. However, with the emergence of several new variants of SARS-CoV-2, the situation deteriorated. When COVID-19-related deaths reached 4.4 million, only 17,400 were registered among children and adolescents under 20 years old, with 47% of those occurring in the 0–9 age group. From the early stages of the outbreak, Chinese researchers reported that children were occasionally infected with the virus, but much less frequently and with milder symptoms than adults. Scientists have attempted to explain the presumed relative resistance of children to SARS-CoV-2 by various factors. Currently, COVID-19 can have a severe course in children. The disease is most severe in the 1-month to 1-year age group, where it is often complicated by the development of MIS-C, accompanied by elevated levels of IFN-γ, IL-1β, IL-10, IL-6, IL-17, and IL-8. Children aged 1 to 5 years generally experience milder forms of the disease. In older age groups, symptoms such as dyspnea and abnormal respiratory rhythm may occur. Thus, age is a key factor influencing the severity of COVID-19 in children. It has been shown that a rapid increase in pro-inflammatory cytokine levels during COVID-19 infection is a warning sign of severe or critical disease progression. However, our literature review indicates that available data on TNF-α and IL-10 are limited and contradictory. Patients were mostly grouped based on disease severity, but the variations in these cytokine levels across pediatric age groups were not well defined. Therefore, clinical and prognostic research regarding their significance is ongoing.</jats:p>