Since 2019, humanity has been relentlessly fi ghting the pandemic caused by the SARS-CoV-2 virus. Respiratory distress syndrome is the main clinical manifestation of COVID-19, which often results in full recovery but can also end fatally. Of interest to modern medicine is a small group of patients in whom the disease persists for months, known as “Long COVID.” This condition predisposes to the development of a rare but life-threatening syndrome, manifested and defi ned as one of the most serious complications of SARS-CoV-2 infection – multisystem Infl ammatory Syndrome in Adults (MIS-A). This syndrome was fi rst described in children and called MIS-C (Multisystem Infl ammatory Syndrome in Children). The affected population consists of patients ≥ 21 years old, regardless of gender. Despite numerous studies, clinical-laboratory and demographic analyses, there are still disagreements regarding the frequency of occurrence, pathogenesis, and diagnostic-therapeutic algorithm for these patients. The purpose of this article is to systematize the congested experience and knowledge, as well as to demonstrate their application in clinical practice.