Gastrointestinal symptoms in COVID-19: the long and the short of it

A large and growing number of patients have persistent gastrointestinal symptoms that they attribute to COVID-19. SARS-CoV-2, the virus that causes COVID-19, replicates within the gut and acute COVID-19 is associated with alteration of the gut microbiome. This article reviews recent observational data related to gastrointestinal symptoms in 'long COVID' and discusses pathophysiologic mechanisms that might explain persistent post-COVID gastrointestinal symptoms.Gastrointestinal symptoms are present in half of the patients with acute COVID-19, persist 6 months after COVID-19 in 10-25% of patients, and are rated as the most bothersome symptom in 11% of all patients. These symptoms include heartburn, constipation, diarrhoea and abdominal pain and decline in prevalence with the passage of time. Long COVID gastrointestinal symptoms are associated with mental health symptoms (anxiety and depression) that predate COVID-19 and also with mental health symptoms that are concurrent, after recovery from COVID-19. The cause of long COVID gastrointestinal symptoms is unknown and hypotheses include the SARS-CoV-2 virus itself, which infects the gastrointestinal tract; COVID-19, which can be accompanied by gut microbiome changes, a profound systemic inflammatory response and critical illness; and/or effects of pandemic stress on gastrointestinal function and symptom perception, which may be unrelated to either SARS-CoV-2 or to COVID-19.New, persistent gastrointestinal symptoms are commonly reported after recovery from COVID-19. The pathophysiology of these symptoms is unknown but likely to be multifactorial.