Abstract Background: Lung ultrasound (LUS) has become an important tool in diagnosing and following an adult patient with COVID-19; however, the literature for the pediatric age group is limited. Herein, we reviewed the up-to-date literatures on ultrasound use for COVID-19 pediatric patients for better management of COVID-19 in children. Methods and Objectives: The search terms “COVID-19,” “SARS-CoV2,” “coronavirus,” “2019-nCoV,” “lung ultrasound,” “sonography,” “adolescents” “children,” “childhood” and “newborn” were searched on the online databases PubMed, Embase and Medline. Articles meeting the inclusion criteria were included in the analysis and review. Results: We identified only fifteen studies to date using LUS to diagnose SARS-CoV-2 infection in children. These studies involved a total of 334 newborns, children and adolescents. Regarding the use of chest X-ray (CXR) and LUS in pediatric patients with COVID-19, we identified six studies with a total of 162 participants, with the following results: 33patients(14.11%) with lung abnormalities on lung US had a normal CXR; however, no patients with normal lung US had abnormalities on the CXR. In addition, regarding the use of computed tomography (CT) and LUS in pediatric patients with COVID-19 infection, we identified five studies with a total of 50 participants and 3 patients(6%) with lung abnormalities on chest LUS had a normal CT. Conclusion: Our findings suggest that LUS is a useful tool in the diagnosis of children and reduction in chest CT assessments may be possible when LUS is used in early diagnosis and follow-up monitoring of COVID-19 pneumonia in the children.

Objective: The purpose of the current study was to determine the difference in intestinal microbiota after delivery between healthy fetuses and fetuses with hyperechogenic bowel during the second trimester and the relationship between fetal echogenic bowel and microbiota. Design: Prospective cohort study. Setting: The Second Affiliated Hospital Of Fujian Medical University，Quan zhou, China. Population: 34 single pregnant women and their fetuses. Methods: Fourteen healthy fetuses (control group), 13 fetuses with echogenic bowel (EB group), and 7 fetuses with echogenic bowel and other abnormalities (C-EB group) were selected. The first meconium after delivery was collected for 16s rRNA sequencing. Results: A total of 69,222 operation classification units were obtained by clustering all high-quality sequences with 97% similarity. There was no significant difference in the Shannon, Simpson, and Chao 1 indices among the three groups. At the phylum level, the intestinal microflora of the three groups were similar.At the genus level, the abundance of Escherichia coli/Shigella in the EB、C-EBgroup was significantly lower than the control group, while the abundance of Staphylococcus, Methylobactrium, and Curvibacter in the EB group was significantly higher than the other groups. There was a difference in abundance of Gammaproteobacteria, Fusobacteria, Enterobacteriaceae, and E. coli in the EB and C-EB groups. Conclusion: The intestinal flora may be related to fetal echogenic bowel via mucus secretion and intestinal gas production.