Gut microbiota and COVID-19: An intriguing pediatric perspective

Table 2 Main findings of the pediatric studies on the association between gut microbiota and coronavirus disease 2019

Ref.	Study design and methods	Population (n)	Main findings
Romano-Keeler et al[44]	Observational cohort study	Twenty-one COVID-19 positive mothers delivering between March and August 2020 with a mean age of 26 (17-42) yr	Delayed cord clamping and skin-to-skin avoided; infants admitted to the NICU with maternal breast milk restricted. Discharge arranged with COVID-19 negative family members. All 21 infants COVID-19 negative at 24 and 48 h. Changes in perinatal care might negatively affect gut microbiome pattern early in life
Nashed et al[40]	Case-control study	595 children aged 0-24 mo	Significantly different abundant species between SARS-CoV-2 positive infants and controls were found. A decreased abundance of Bifidobacterium bifidum and Akkermansia muciniphila in positive samples (both linked to protection against inflammation) was found
Xu et al[43]	Case-control study	(1) 9 children diagnosed with COVID-19 aged 7-139 mo; and (2) 14 age-matched healthy control children	Altered microbiome in COVID-19 children, with increased abundance of opportunistic pathogenic and environmental bacteria such as Pseudomonas, Herbaspirillum, and Burkholderia both in the upper respiratory tract and the gut was found. Dysbiosis up to 25-28 d in different subjects was reported

SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2; COVID-19: Coronavirus disease 2019; NICU: Neonatal Intensive Care Unit.