Clinical characteristics of COVID-19 severity and dysbiosis effect [12]

COVID-19 severity typeCriteriaDysbiosis effect
MildClinical symptoms minimal, no imaging consistent for pneumoniaHad viral clearance as evidenced by their fecal samples and these patients showed symptomatic recovery
ModerateFever, upper respiratory symptoms, and imaging evidence of pneumonia
Severe(1) Respiratory distress (i.e., RR > 30)
(2) SpO2 less than 93% at rest
(3) PaO2/FiO2 < 300 mmHg (1 kPa ≈ 7.50 mmHg)
Depletion of beneficial commensals, affecting the breakdown of SCFAs and L-isoleucine biosynthesis, which in turn impaired viral clearance and symptomatic recovery resulting in persistent metabolic dysfunction
Critically ill(1) Respiratory failure requiring intubation and ventilation
(2) Shock
(3) Organ failure, requiring ICU monitoring and treatment