Proceedings of the International scientific and practical conference ―Science, technology and art in global context‖ (October 14-16, 2025) / Publisher website: www.naukainfo.com. – Warsaw, Poland, 2025. - 72 p.

46 UDC 616.9 Olkhovska Olga Mykolayivna Doctor of Medical Sciences. Professor Kolesnyk Yana Volodymyrivna Doctor of Philosophy, Associate Professor Slepchenko Margarita Yuriivna Doctor of Philosophy, Assistant Kharkiv National Medical University, Kharkiv, Ukraine FEATURES OF INFECTIOUS MONONUCLEOSIS WITH AN UNFAVORABLE COURSE IN CHILDREN Abstract: A comparison of clinical symptoms and results of additional examination of 110 children at the onset of infectious mononucleosis with different variants of the further course of the disease was carried out. Clinical and laboratory and instrumental signs were determined, on the basis of which it is possible to predict an unfavorable course of infectious mononucleosis. Keywords: infectious mononucleosis, prognosis, children. Herpesvirus infections remain common in the human population, with infectious mononucleosis (IM) caused by Epstein-Barr virus being the most common in children. After the disease, both long-term persistence of the virus and the development of lymphoproliferative syndrome are likely [1]. IM caused by Epstein- Barr virus is associated with an increased risk in malignancy, particularly hematologic malignancies [2]. Infectious mononucleosis may be a risk factor for myalgic encephalomyelitis/chronic fatigue syndrome [3]. Therefore, it is important to identify factors of unfavorable development of IM at the onset. Early prediction of