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Indicators of vitamin D in case of Coronavirus infection COVID-19 in children

Purpose — to determine and compare vitamin D levels in children diagnosed with COVID-19-associated pneumonia and healthy children. Materials and methods. The study involved 90 children. The main group consisted of 75 inpatient children with a diagnosis of COVID-19-associated pneumonia (positive PCR — polymerase chain reaction with reverse transcription). Patients in the main group were divided into 2 subgroups: subgroup I consisted of 49 patients with a pneumonia of moderate course, and subgroup II — 26 patients with a pneumonia of severe course. The control group consisted of 15 practically healthy children. The scheme of examination of sick children included anamnestic data, the use of clinical, instrumental and laboratory, immunological examination methods. The concentration of vitamin D in the blood serum of sick and healthy children was determined by the method of enzyme3linked immunosorbent assay (ELISA). The indicators were measured on a Stat Fax 4700 device using a Pishqaman reactive kit (made in Germany). Results. The concentration of vitamin D in blood serum was 1.8 times lower in subgroup I and 2.0 times in subgroup II, compared with the control group. The average values of vitamin D in blood serum compared with the control group were <1.1 times lower in the age group <1 year, 1.1 times lower in the age group 1–3 years, and 2.3 times lower in the age group >3 years. Conclusions. Based on our research, it can be concluded that there is a relationship between vitamin D deficiency and COVID-19. Thus, the average level of vitamin D was lower in children with COVID-19-associated pneumonia, and varied depending on the severity of the disease (more pronounced changes were observed in severe pneumonia). There are also differences in vitamin D levels in the age groups of children with COVID-19-associated pneumonia: in children from age groups under 1 year and 1–3 years old the decrease in serum vitamin D level is less pronounced than in the age group over 3 years old. The main mechanisms of vitamin D involvement in the immune modulation process in COVID-19 require further study. The research was carried out in accordance with the principles of the Helsinki declaration. The study protocol was approved by the Local ethics committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interest was declared by the authors. Key words: children, COVID-19, vitamin D.