The gut microbiome plays a dynamic role in initiating, adapting, and regulating the human immune response. A major part of the body’s immune cells is found in the intestine, making the gut microbiome a decisive player in regulating the immune response in the gut and other organs. Studies have also highlighted evidence for crosstalk between the gut and lung microbiomes – the ‘gut-lung axis’, with the gut microbiota modulating lung immunity. Changes in the composition of the gut microbiome have been linked to alterations in the immune responses and homeostasis of the lungs and increased susceptibility to respiratory diseases.
Coronavirus disease is primarily a respiratory infection, but it also affects the gastrointestinal (GI) tract. GI symptoms such as diarrhoea, vomiting, nausea, loss of appetite, GI bleed, and abdominal pain have been reported in patients with COVID, sometimes as the only presenting symptoms. Patients with disturbed gut flora may be more susceptible to COVID-19.
Probiotics have been used for preventing and treating respiratory tract infections caused by viruses. Several possible mechanisms have been postulated, including direct probiotic–virus interaction, production of antiviral inhibitory metabolites, and stimulation of the immune system through various signalling pathways. A possible role in preventing viral infections like COVID-19 has been suggested. Administration of lactobacilli and bifidobacteria has been shown to overcome the gut dysbiosis induced by SARS-CoV2 infection. A meta-analysis demonstrated decreased severity or shortened duration of disease with probiotics like Lactobacillus and Bifidobacterium.
As new data emerge, a role for select strains of probiotics in ameliorating this disease will be welcome news.
Dr Philip Abraham, Consultant Gastroenterologist and Hepatologist, P D Hinduja Hospital and Hinduja Healthcare Surgical, Mumbai