Serum IL-6 and IL-18 responses in COVID-19 in children: the role of vitamin D status in a cohort from Azerbaijan

Introduction: Coronavirus disease 2019 (COVID-19) may trigger inflammatory responses in children, and vitamin D is known to play an important role in immune regulation. Methods: This study investigated the effects of COVID-19 infection and vitamin D status on inflammatory cytokine levels in children during the pandemic. A cohort of 170 children aged 1-17 years with PCR-confirmed SARS-CoV-2 infection was enrolled. Serum levels of IL-6 and IL-18 were analyzed in relation to vitamin D status and COVID-19 diagnosis. Results: Children with PCR-confirmed COVID-19 exhibited higher serum levels of IL-6 and IL-18 compared with healthy controls. Children with vitamin D deficiency had higher cytokine levels compared with those with normal vitamin D levels, although these differences were not statistically significant. Discussion: The findings suggest that low vitamin D levels may influence the increase in the studied cytokines; however, the current results do not fully confirm this relationship. These observations highlight the need for further large-scale and prospective studies to better understand the immunomodulatory role of vitamin D in pediatric COVID-19 patients.