The Role of Hematological Parameters in Children with COVID-19, MIS- C, and Other Viral Infections

Objective: It is known that coronavirus disease-2019 (COVID-19) showed a clinical course with milder symptoms in children than in adults. However, a multisystem inflammatory syndrome in children (MIS-C), which developed 2-4 weeks after COVID-19 infection, emerged in April 2021. Other respiratory viruses such as influenza, respiratory syncytial virus, and parainfluenza spread worldwide after loosening pandemic restrictions. Pediatricians were challenged to distinguish COVID-19, MIS-C, and other viral infections from each other. Herein, we have aimed to determine basic, simple hematological parameters that can predict the prognosis and outcomes of the patients with COVID-19 and MIS-C. Method: In this study, 300 pediatric inpatients including those with MIS-C, COVID-19, and other respiratory virus infections admitted to Ege University Faculty of Medicine between January 2018 and September 2021, were retrospectively evaluated. Results: The neutrophil-to-lymphocyte ratio (NLR), neutrophil- to-monocyte ratio (NMR), derived NLR, and the systemic inflammatory index were higher in the MIS- C patients compared to others. The lymphocyte-to-monocyte ratio (LMR) and platelet- to-lymphocyte ratio ( PLR) were lower in children with COVID- 19 disease than those with MIS-C (p<0.05). Conclusions: In this study, we have shown that commonly used hematological tests, especially higher values of NLR, NMR for children with MIS- C, and lower levels of LMR for children with COVID-19, are significant and can help to determine the possible disease course of children at an early stage.