Complete Blood Count in Children With COVID-19: A Predictor of Disease Severity.

Blood count abnormalities are frequent in patients with severe COVID-19 disease and there is still a lack of information in pediatric complete blood count (CBC) results. Thus, this study aims to correlate the CBC in the emergency room of children with COVID-19 between 0 and 10 years old and the clinical severity of the disease. A retrospective cohort study was performed in children with COVID-19 who collected at the emergency room CBC, C-reactive protein (CRP), platelet to lymphocyte ratio (PLR), neutrophil to lymphocyte ratio (NLR), neutrophil to monocyte ratio (NMR), lymphocyte to neutrophil ratio (LNR), lymphocyte to monocyte ratio (LMR), monocyte to neutrophil ratio (MNR) and monocyte to lymphocyte ratio (MLR). In total, demographic data from 93 children with median age of 19 months (0.3-126), 60.2% males, were included. The main changes in the CBC were atypical lymphocytes (51.6%) and eosinopenia (49.5%). From 69 hospitalized children, 21 were considered severe. There was no association between age, gender, and CRP value with clinical severity. The presence of underlying disease was five times higher (odds ratio [OR] = 5.08) in patients who required hospitalization and a higher NLR value was 54% (OR = 1.54) more likely to occur. Eosinopenia was three times more frequent in inpatients with disease severity criteria (OR = 3.05). In conclusion, children younger than 10 years of age with COVID-19 have changes in the CBC collected in the emergency room, mainly atypical lymphocytes and eosinopenia. The presence of a comorbidity or a higher NLR increases the chance of hospitalization. In addition, eosinopenia was a predictor of severity in inpatient children due to COVID-19.