Long COVID

also known for post-acute sequelae of COVID-19

describes the people who have the signs and symptoms that continue or develop after the acute COVID-19 phase. Long COVID patients suffer from an inflammation or host responses towards the virus approximately 4 weeks after initial infection with the SARS CoV-2 virus and continue for an uncharacterized duration. Anyone infected with COVID-19 before could experience long-COVID conditions

including the patients who were infected with SARS CoV-2 virus confirmed by tests and those who never knew they had an infection early. People with long COVID may experience health problems from different types and combinations of symptoms over time

such as fatigue

dyspnea

cognitive impairments

and gastrointestinal (GI) symptoms (

e.g.

nausea

vomiting

diarrhea

decreased or loss of appetite

abdominal pain

and dysgeusia). The critical role of the microbiome in these GI symptoms and long COVID were reported in clinical patients and experimental models. Here

we provide an overall view of the critical role of the GI tract and microbiome in the development of long COVID

including the clinical GI symptoms in patients

dysbiosis

viral–microbiome interactions

barrier function

and inflammatory bowel disease patients with long COVID. We highlight the potential mechanisms and possible treatment based on GI health and microbiome. Finally

we discuss challenges and future direction in the long COVID clinic and research.