[Justification of the need to normalize vitamin D status for immunoprophylaxis]

Currently, there is an increase in the resistance of microorganisms to the available arsenal of antimicrobial drugs, which makes it necessary to maintain and stimulate the body's own immune-protective properties. The main extraskeletal effect of vitamin D activity is associated with the homeostasis of the immune system. The role of vitamin D in reducing the risk of infection with infectious agents has been studied for a long time. Literature search on the effective use of vitamin D for immunoprophylaxis was carried out in Scopus, Web of Science, PubMed, clinicaltrials.gov databases over the past 10 years for related keywords: vitamin D, immunoprophylaxis. Vitamin D stimulates the synthesis of antimicrobial peptides, cathelicidins and defensins, which exhibit broad-spectrum activity against viruses, bacteria and fungal infections; reduces the concentration of pro-inflammatory cytokines; increases the concentration of anti-inflammatory cytokines. Vitamin D is also involved in cell differentiation, maturation and proliferation of immune cells. The article presents the literature review in order to justify additional intake of vitamin D in case of diagnosis of its deficiency and insufficiency for the purpose of immunoprophylaxis in children and adults, especially in risk groups (elderly age, pregnant women, patients with chronic diseases of respiratory, endocrine and urinary systems, gastrointestinal tract, and infectious diseases). Inclusion of vitamin D in the diet as a dietary supplement, as well as fortification of products with it, can be an effective measure to reduce the risk of both morbidity and mortality, especially during the period of quarantine measures.