SUMMARY
Abstract. Recently, the number of cases of infectious mononucleosis has increased among adults, as well as with the course of the disease for more than 3 months. The Epstein-Barr virus is capable of attacking immunocompetent cells, causing lymphadenopathy, hepato- and splenomegaly, being stored forever in the body's lymphocytes, and causing an immunodeficient state. The aim of the study. To find out the state of post-vaccination immunity to diphtheria and tetanus in adults who have contracted EBV infection. Materials and methods. 79 adults (1 group) with MI were examined: 30 people with a mild (L) form of the disease, 38 people with a moderate (SrT) form, 11 people with a severe (T) form, and 25 adults (2 groups) with chronic EBV infection (CHEBVI). The control group consisted of 41 people (K group). The level of antibodies to diphtheria and tetanus toxin was measured by ELISA according to the instructions. According to WHO recommendations, the protective level of antibodies against these infections was considered ? 0.1 IU/ml. The results. It was established that in adults who fell ill with infectious mononucleosis in a mild form, a decrease in the level of antibodies to diphtheria and tetanus below the protective level (? 0.1 IU/ml) was not observed. 44.7 % of persons who fell ill with infectious mononucleosis in a moderate form did not have protective levels of antibodies to diphtheria, 34.2 % before tetanus, 54.5 % of people who fell ill with severe infectious mononucleosis did not have a protective level of antibodies against diphtheria and tetanus. The number of adults in the control group who did not have a protective level of antibodies to tetanus was 12.1 %, to diphtheria – 26.7 %. During the examination of 25 adults with CHEBVI, it was established that 76.0 % did not have a protective level of antibodies to diphtheria, 64.0 % to tetanus. Conclusions. In adults who have contracted the acute and chronic form of EBV infection, there is a decrease in the level of anti-tetanus and anti-diphtheria antitoxins, and an increase in the percentage of people without a protective level of antibodies to these infections. The percentage of patients with CHEBVI who did not have a protective level of antibodies was significantly higher than among persons who contracted infectious mononucleosis. The obtained data indicate the need to monitor the immune status of persons who have contracted EBV infection and recommend vaccination in case of a low level of antibodies to diphtheria and tetanus or their absence.