Post‑COVID‑19 syndrome in children (Review).

The persistence of symptoms for a long time after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is now familiar as post-COVID syndrome (PCS). To the best of our knowledge, the risk of long-term clinical outcomes in children after SARS-CoV-2 infection is still unclear. Unlike in adults, current evidence suggests a lower prevalence of persistent symptoms in children. However, since several studies are characterized by great heterogeneity, it is difficult to accurately estimate the exact incidence of PCS in children. The presence and course of recovery depend on risk factors that are more common in adults than children. Proposed pathophysiological mechanisms in PCS in children include age-dependent immune responses, angiotensin-converting enzyme 2 expression, blood-brain barrier development or social issues affecting children behavior, such as school closure and social isolation. However, further longitudinal studies are required for unanswered issues to be clarified. The aim of the present review is to describe the long-term symptoms per biological system in children, potential risk factors and the role of the immune system in the presence of PCS.