Effective rehabilitation of patients who have had a SARS CoV-2 infection is essential to prevent re-infections and will improve the quality of life of people and reduce the burden on the healthcare system. Muramylpeptides are used in the prevention of seasonal diseases in children and adults in order to correct immunodeficiency states and prevent infectious complications. The aim of this study was to study the dynamic changes in the state of cellular factors of innate immunity and the levels of anxiety and depression in patients treated with glucosaminyl muramyl dipeptide (GMDP). 

Patients who underwent mild to moderate COVID-19 (N=60, mean age 54 ± 11.7 years) were randomized to the study group (30 people, 15 men and 15 women) who received 2 courses of licopid 1 mg twice per day and a comparison group (30 people, 15 men and 15 women). Analysis of the phenotypic and functional characteristics of the cellular factors of the innate immune response was carried out before the start of immunomodulatory therapy, immediately after the end of the course, and also after 6 months. observations. To assess the quality of life of all patients, the SF-36 Health Status Survey and HADS questionnaires were used before the use of licopid, at the end of the course and after 6 months of follow-up.

In the course of assessing the effect of immunomodulatory therapy on the parameters of innate immunity of patients at the stage of rehabilitation after suffering COVID-19, an increase in the protective cytolytic activity of CD16+, CD8+Gr+ cells, as well as a persistent increase in the expression of TLR2, TLR4 and TLR9 was found, which indicates the restoration of antigenic recognition and presentations at the level of the monocytic link of the immune system. The use of GMDP as an immunomodulatory agent resulted in an 8-fold decrease in the frequency and severity of respiratory infections due to an increase in the total monocyte count, which persisted for 6 months from the start of therapy, while the use of systemic antibiotic therapy was not required, while in the comparison group - 7 people were forced to resort to this therapy due to the severity of acute respiratory infections. When analyzing the assessment of the quality of life of patients against the background of the therapy, patients showed positive dynamics in role functioning, general assessment of their health status, and an increase in physical and mental well-being during 6 months of observation. In the comparison group, there was no improvement in the psycho-emotional state of patients. 

In this study, for the first time, it was found that the correction of immunological parameters when exposed to GMDP after a previous illness contributed not only to a decrease in the frequency and severity of respiratory infections, but also to an improvement in the psycho-emotional state of patients, and a decrease in anxiety and depression.