It was aimed to investigate the relationship between SARS-CoV-2 infection severity and free and bioavailable vitamin D levels. This study was planned as a case-control study with patients hospitalized in the Haseki Training and Research Hospital Pediatric Infection Service. A total of 82 children, including at least 20 patients in each group were included in the study. The study group was divided into three groups according to COVID-19 WHO clinical progression Scale: unaffected (Group 1), mild (Group 2) and moderate (group 3). In order to investigate the relationship between disease severity and free and bioavailable vitamin D; 25OH vitamin d (μg/L), albumin (g/l) and VDBP levels (ELISA) were used. Vitamin D metabolites were calculated by using Bikle and Vermeulen methods (free Vitamin D BIKLE, free vitamin DVERMEULEN, bioavailable vitamin D). And these three vitamin D parameter levels were compared between groups.
There were many studies in the literature discussing the effects of vitamin D deficiency and the role of vitamin D supplementation in SARS-CoV-2 patients. Combined with the possible impact of vitamin D on the pathogenesis of SARS-CoV-2 infection, it is concluded that VDBP-regulated bioavailable and free vitamin D concentrations modulate the human immune system response to viral infections. Because of the gap in the literature, it was emphasized that studies should focus on vitamin D binding protein (VDBP) and gene polymorphism. In this study, it was aimed to investigate the relationship between SARS-CoV-2 infection severity and free and bioavailable vitamin D levels.