Abstract
The ongoing pandemic of coronavirus disease 2019 (COVID-19) is emerging as a public health crisis worldwide. Patients with COVID-19 range from being asymptomatic to suffering from severe pneumonia, acute respiratory distress syndrome (ARDS), and multiple organ failure (MOF). Gastrointestinal (GI) symptoms have been reported in a number of patients with COVID-19, suggesting that GI microbiota may play a role in the pathogeneses of the disease. Theoretically, patients with confirmed inflammatory bowel disease (IBD) treated with immune-based therapies may be at a higher risk of manifesting a severe form of COVID-19, owing to immune system impairment. This hypothesis has evoked the concerns of patients and treating physicians throughout the pandemic. However, surprisingly, the findings of a number of studies show that immunosuppressive therapies, such as anti-TNF agents, could reduce the severity of symptoms associated with Covid-19. Dysbiosis of gut microbiota, characteristic of IBD patients, can be positively changed after using anti-TNF agents. Vitamin D has been revealed to have a profound effect on reducing the viral infections, aside from its role in modulating the gut microbiome. In this review, we discuss possible susceptibility of IBD patients to SARS-CoV-2 infection, the impact of immunosuppressive therapies on the course of SARS-CoV-2 infection in patients with IBD, and the potential protective role of gut microbiota against COVID-19 in patients with IBD in the presence of normal vitamin D levels.