COVID-19, having not completed its epidemic development, gradually passes into the stage of prolonged diseases, which at the clinical level is designated as «postcovid syndrome». The symptomatology of these negative phenomena is quite diverse, covers the dysfunction of many organs and systems, and deserves the formulation of polymorphism of secondary and delayed complications. They are based on the consequences of the transferred acute phase of inflammation, systemic prolonged metabolic and structural disorders, including the studied genetic disorders. Possible causes of polymorphism of disorders and their manifestations in the postcovid period are considered.