Modern infectious mononucleosis in children: results of own observations

Background. The relevance of modern infectious mononucleosis (IM) is due to its high prevalence, lifelong persistence of the pathogen in the human body, virus-induced immunosuppression during active viral replication, and the lack of effective treatments and preventive measures. Objective. To analyze the clinical and epidemiological aspects of infectious mononucleosis in children at the present stage. Materials and methods. The study included 316 patients hospitalized at the Yaroslavl Regional Infectious Diseases Clinical Hospital between 2021 and 2023. Results and discussion. The most affected age groups were children aged 4-6 and 11-17 years. The characteristic symptoms of IM remain fever, nasal obstruction, tonsillitis, lymphadenopathy, exanthema, and hepatosplenomegaly. Icteric forms of the disease were rare. In most patients, the onset of rash was associated with the administration of semi-synthetic penicillins at the prehospital stage. Atypical mononuclear cells were detected in only 52.2% of children, making diagnosis based solely on a complete blood count challenging. Epstein-Barr virus (EBV) alone or in combination with cytomegalovirus (CMV) was the dominant cause of primary infection. Reactivation was primarily caused by CMV following primary EBV infection in almost all patients. In most children with tonsillar exudate, a low C-reactive protein level indicated a viral etiology of tonsillitis and argued against the need for antibiotic therapy.