Altered Gut Microbiota and Predicted Immune Dysregulation in Early Childhood SARS-CoV-2 Infection

Area of Science:

• Microbiology
• Immunology
• Pediatrics

Background:

• The gut microbiome is vital for immune regulation, especially during rapid development in early childhood.
• Limited data exist on how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection impacts the pediatric gut microbiome.
• Understanding these changes is crucial for assessing potential long-term health consequences.

Purpose of the Study:

• To characterize gut microbiome alterations in infants and toddlers with coronavirus disease 2019 (COVID-19).
• To investigate associated changes in immune-related pathways.
• To explore the implications for immune development in early childhood.

Main Methods:

• 16S rRNA gene sequencing of stool samples from 18 children under 2 with COVID-19 and 7 healthy controls.
• Analysis of gut microbiome composition, diversity (alpha and beta diversity), and predicted functional pathways.
• Comparison between COVID-19-affected children and healthy controls.

Main Results:

• COVID-19 was associated with increased Bacteroidota and Bacillota, and decreased Actinomycetota and Pseudomonadota.
• Specific genera like *Bifidobacterium*, *Escherichia*, and *Streptococcus* were more abundant, while *Faecalibacterium*, *Clostridium*, and *Ruminococcus* were less abundant in COVID-19 cases.
• Reduced alpha diversity and altered beta diversity indicated gut dysbiosis. Predictive analysis showed downregulated immune pathways (IL-17, NLR, TLR signaling).

Conclusions:

• SARS-CoV-2 infection in early childhood induces gut dysbiosis.
• The infection suppresses critical immune signaling pathways, potentially impairing mucosal immunity and viral clearance.
• These early-life microbial disruptions may have lasting effects on immune system development.