Limitations
Our study has a number of limitations. First, like all ultrasound examinations, it is an operator-dependent technique and is associated to a learning curve. To minimize variability, even though the ultrasounds were performed by only two emergency pediatricians with lung ultrasound training, the rescued images were subsequently reviewed by the same operators (Cohen’s kappa .80). Secondly, the ultrasound aspects described are not pathognomonic of SARS-CoV-2infection since they are artifacts also found in the course of other lung diseases (e.g. bronchiolitis). These ultrasound aspects, in fact, have a fundamental role for the pediatrician if integrated with the assessment of the child affected by SARS-CoV-2in the classification of the severity of the disease and in the programming of other laboratory and instrumental tests but do not allow the current state of our knowledge to perform diagnosis of COVID-19.