However, vaccination, according to the results of our work, did not statistically significantly lead to changes in lymphocyte parameters (CD45+CD3−CD19+, CD45+CD3+CD19−, CD45+CD3+CD4+, CD45+CD3+CD8+, CD45+CD3+CD16+CD56+); there was only an increase in relative counts (%) of CD45+CD3+CD19-lymphocytes and a decrease in relative counts (%) of CD45+CD3−CD19+ lymphocytes in the group of patients vaccinated with one dose, which is not confirmed by the data obtained in patients with CVID vaccinated with two doses. The gene discussed is CD19; the disease is common variable immunodeficiency.