COVID-19 in Infants and Children under 2 Years—Could Lung Ultrasound Score Be Correlated with Biomarkers and Symptoms?

Introduction: It is already well known that infants and children infected with COVID-19 develop mild to moderate forms of the disease, with fever and oropharyngeal congestion being the most common symptoms. However, there are instances when patients claim to be experiencing respiratory symptoms. Because of the repeated lung examinations required in these situations, non-irradiating imaging techniques are preferred. This study’s objective is to ascertain the value of lung ultrasonography (LUS) in the medical management of these specific cases. Methods: Infants and children under two years old with SARS-CoV-2 infection were evaluated using LUS. Patients with other respiratory pathologies were excluded by using specific tests. The LUS score (LUSS) was correlated with biomarkers and clinical findings using the Mann–Whitney U test and Spearman’s rank correlation rho. Results: The LUSS for each patient varied from 1 to 8 points out of a maximum of 36 points. The arithmetic mean was 4.47 ± 2.36 (S.D), while the 95% CI for the arithmetic mean was 3.33 to 5.61. Sparse B-lines were present in all enrolled infants and children (100%), while only 36.84% developed alveolar syndrome (confluent B-lines). The lung changes were correlated with their biomarkers, specifically inflammatory markers. The correlation between LUSS and LDH, D-dimers, and IL-6 was a strongly positive one with rho = 0.55 (p = 0.001, 95% CI 0.13 to 0.80) between the LUSS and D-dimer levels and rho = 0.60 (p = 0.03, 95% CI 0.04 to 0.87) between LUSS and D-dimer levels at symptomatic infants and children (with respiratory involvement). Conclusions: Infants and children under the age of two are prone to develop mild forms of COVID-19 disease with a B-line pattern on LUS, although inflammatory markers have elevated blood levels. Despite the small sample, D-dimer levels and O(2) saturation were correlated with LUSS in patients with respiratory involvement, while similar results were also found in the entire lot.