Abstract
The gut flora modulates immune responses and influences COVID-19 severity. SARS-CoV-2 disrupts the gut microbiota, causing dysbiosis, increased intestinal permeability, and systemic inflammation and worsening clinical outcomes. Dysbiosis correlates with elevated inflammatory markers, such as CRP and PCT, contributing to severe complications. Studies show that COVID-19 patients have reduced beneficial bacteria, such as Faecalibacterium prausnitzii and Bifidobacterium spp., alongside increased opportunistic pathogens. This review explores how gut microbiota impacts COVID-19 through predictive microbial signatures and immunomodulatory mechanisms. Therapeutic strategies, including probiotics, prebiotics, and fiber-rich diets, may restore microbial balance, reduce inflammation, and support recovery. Additionally, we examine the effects of antiviral and immunomodulatory therapies on the gut microbiota and their role in post-COVID-19 rehabilitation. Understanding the gut-lung axis in SARS-CoV-2 pathogenesis may reveal microbiota-targeted treatments to improve outcomes and prevent complications. As the host organ with the highest microbial diversity, the gut plays a crucial role in viral infections and warrants further research.