# Clinical and Paraclinical Peculiarities of SARS-CoV-2 and Influenza Infections in Children: A Comparative Study

## TL;DR

This study compares how SARS-CoV-2 and influenza affect children, focusing on symptoms and blood markers to help distinguish and predict complications.

## Contribution

The study identifies monocyte levels and lymphocyte/monocyte ratios as novel indicators for differentiating and predicting complications in pediatric SARS-CoV-2 and influenza infections.

## Key findings

- SARS-CoV-2 infections in children are more likely to involve digestive symptoms compared to influenza.
- Monocytes and lymphocyte/monocyte ratios are significantly higher in SARS-CoV-2 cases.
- Lymphocyte/monocyte ratios and neutrophil/lymphocyte ratios predict hospitalization duration and respiratory distress.

## Abstract

Background: SARS-CoV-2 and influenza can present with similar clinical pictures in children, with symptoms and paraclinical particularities which might aid in the differentiation of the two entities and which can be suggestive of various complications. The present study aims to identify clinical and paraclinical differences between pediatric SARS-CoV-2 and influenza infection and to assess the utility of hematological parameters for prediction of their related complications. Methods: In this study, 266 children were retrospectively enrolled, divided into two groups: 129 children diagnosed with SARS-CoV-2 infection and 137 children infected with influenza. In each case, particular symptoms were recorded, as well as hospitalization duration, pediatric intensive care unit (PICU) admission or O2 supplementation requirement. Parameters of the hemoleucogram and biochemistry parameters were also collected for comparative assessment. Results: SARS-CoV-2 infections were more commonly associated with digestive symptoms, whereas influenza infections implied longer hospital stays and higher likelihood of PICU admission necessity. Monocytes and lymphocyte/monocyte ratios (LMRs) were significantly higher in the SARS-CoV-2 group (p < 0.01, p = 0.02). Several hematological parameters, such as neutrophil/lymphocyte ratios, correlated with hospitalization duration in SARS-CoV-2 and influenza B infections (p < 0.01, p = 0.01), whereas LMR was predictive of respiratory distress (p = 0.02) in the same study groups. Conclusions: According to the study, monocyte levels and LMR can aid in the distinction of pediatric SARS-CoV-2 and influenza infections and LMR and NLR can be used particularly as predictors of complicated course of these infections.