Coronavirus Infection and Diarrhea

There have been increasing reports of SARS-CoV2 infected individuals who show symptoms of diarrhea. More than ever this is the time to ensure your gut is healthy, read on to find out more about how this virus affects gut cells and what can be done. This month we review a paper published in Clinical Gastroenterology and Hepatology.

In January, Hubei province, China was devastated by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) that causes COVID-19 disease. Since then, COVID-19 has taken hold of the globe, affecting 210 countries, resulting in greater than 140 000 deaths (accurate at time of publication). This pandemic is a worldwide emergency.

SARS-CoV2 & Our Guts

SARS-CoV2 has a spikey outer surface that connects with a receptor on human cells, called angiotensin-converting enzyme 2 (ACE2). The ACE2 receptor is found not only on lung cells but also on cells of the oesophagus and epithelial cells which line the inner surface of the small and large intestines. It is thought the virus affects intestinal permeability causing malabsorption. In addition, animal models have demonstrated ACE2 changes are associated with colitis, increasing intestinal inflammation and diarrhea. We know SARS-CoV2 can be found in saliva and vomit but also your stools, known as viral-shedding.

COVID-19 Diarrhea

In a healthy adult, your stool should look smooth and sausage-shaped, and most people relieve themselves once or twice a day (Type 4 see the Bristol Stool chart, below). However, those who have had severe COVID-19 symptoms have also reported loose stools with defaecation (passing stools) at a frequency of more than three times a day. The first reported case in the United States showed diarrhea-type symptoms for two consecutive days.

The Bristol Stool Chart

What can be done?

With no vaccine or effective anti-viral drugs at the moment, this makes hand washing absolutely essential and in health-care settings PPE clothing critical. Those with severe COVID-19 infections are treated with a cocktail of drugs which in some people also result in an upset tummy. Interestingly, the authors report that China’s National Health Commission recommended the use of probiotics for the treatment of patients with severe COVID-19 to maintain a balance of intestinal microbes and to reduce secondary infection. If you are a healthy adult, with no underlying health conditions, a healthy microbiota is barrier to infection by pathogens, so it is possible that taking an effective probiotic every day you could slightly lower risk of contracting severe COVID-19.    


COVID-19 is a respiratory disease but in 10% of cases infected people experience unpleasant diarrhea symptoms. The authors state that individuals who display diarrhea with no respiratory symptoms should be tested for SARS-CoV2 and that bowel disruptions are being under-estimated and under-reported. Probiotics will balance your gut microbes and offer some protection against unpleasant viral diarrhea.


This post has been written by THBC team who are active researchers in infectious microbiology