The gut-brain axis in long COVID

Long COVID-19, also known as post-acute sequelae of SARS-CoV-2 infection (PASC), is a complex multisystem disorder characterized by persistent neurological, gastrointestinal, and psychological symptoms. Emerging evidence suggests that dysfunction of the gut-brain axis plays an important role in the development and persistence of Long COVID manifestations. SARS-CoV-2 infection may cause long-term alterations in gut microbiota composition, resulting in dysbiosis, impaired intestinal barrier integrity, and chronic immune activation. Reduced abundance of beneficial microorganisms and decreased production of microbial metabolites, particularly short-chain fatty acids, may disrupt intestinal homeostasis and neuroimmune communication. Increased intestinal permeability and inflammatory signaling can contribute to systemic inflammation, vagus nerve dysfunction, and neuroinflammatory processes associated with cognitive impairment, fatigue, mood disturbances, and gastrointestinal symptoms. Therapeutic strategies targeting the gut-brain axis, including probiotics, prebiotics, postbiotics, fecal microbiota transplantation, and vagus nerve stimulation, represent promising approaches for symptom management. Further research is required to clarify their efficacy and establish personalized interventions. Improved understanding of gut-brain interactions in Long COVID may support the discovery of new biomarkers and targeted therapies for post-infectious disorders.