Study population
Initially, 2394 children with suspected COVID-19 infection at the first our emergency department examination underwent nasopharyngeal swab for SARS-CoV-2from the 27 of March 2020 to June the 1st2020. Of 55 children with positive swab for SARS-CoV-2, five were excluded for comorbidity: immunodeficiency (one), cerebral palsy (two), neuromuscular diseases (two). Four children were excluded because they were discharged, in six children first LUS was not performed for absence of operators while in ten patients the LUS follow up was not done. A total of 30 children were enrolled in the study (Figure 1).