Many aspects of the COVID-19 infection, especially its complications and longterm health consequences, are still unknown. Various reactive changes in the blood test during the course of leukemia have been published. Leukocytosis [1], leukopenia [2, 3, 4], neutrophilia [5, 6], lymphocytosis and lymphocytopia [3, 7], thrombocytopenia and, rarely, thrombocytosis [2, 8, 9] were found most often. The detected changes were usually not subject to monitoring in the patient. There are reports of the diagnosis of leukemia after a recent infection with COVID-19. Therefore, studying the features of the clinical picture and hematopoiesis in such patients during the course of a viral infection, as well as in the initial manifestations of leukemia, is relevant.