Introduction. The COVID-19 epidemic is the largest pandemic in modern history. To date,
according to WHO, more than 670 million cases of COVID-19 infection have been offi cially
registered, but, according to experts, the real number of COVID-19 cases is much higher. The prevalence of the pandemic led the most massive vaccination in history, and even after the start
of vaccination campaigns, the spread of the disease has not radically decreased. Wide-range
immunization of the population was chosen as one of the strategies to combat the pandemic; at the same time, confl icting data appear in the scientifi c literature on the effect of the presence of specifi c immunity on the course and outcome of the disease.
The aim of this study is the search of correlation between the presence of specifi c T cell-mediated and humoral immune response in COVID-naive patients and the outcome of the disease.
Material and methods. Using the ELISpot it was determined the presence of cellular immunity to the most important targets (S-, N-, M-proteins) of SARS-CoV-2 (delta strain) in previously virus-naive patients (n = 97). Qualitative determination of IgG to various epitopes of SARS-CoV-2 was performed using a multiplex assay. A subgroup with more stringent inclusion criteria was identifi ed to minimize the impact of comorbidity and patient age on disease outcome (n = 40).
Results. On the 8th day of illness, 100 % of patients did not have T-cell immunity. Its formation was completed by the 17th day of the disease. The highest survival rate of patients was in groups with the presence of both specifi c humoral and T-cell immunity and in patients without both of the types of specifi c immunity (statistically not signifi cant). The absence of comorbidity (obesity, diabetes, neurodegenerative
diseases, oncology) and the young age of the patient did
not signifi cantly affect the result.
Conclusion. Based on the results of the study, we did not fi nd a signifi cant correlation between the presence of humoral or cellular immunity and the outcome of the disease in previously unimmunized patients, both in the general patient group and in the group of patients with
additional inclusion criteria.