Faecal-Oral Transmission of COVID-19

The coronaviruses that cause SARS, MERS and COVID-19 can all infect cells in the gastrointestinal tract. These viruses have been found in biopsy specimens of the gut wall, and in the faeces of infected people, including those who had cleared the infection from the respiratory tract but who continued to shed it in their faeces. In COVID-19, the SARS-CoV-2 virus may be shed for prolonged periods of time (often several weeks) after respiratory symptoms have subsided. Nevertheless, there is not compelling evidence for spread from faeces via the faecal-oral route. An enteric source of the virus could explain some cases of transmission where the source is “unknown”. In some cases, respiratory symptoms of COVID-19 infection are preceded by gastrointestinal tract symptoms, including abdominal discomfort, nausea, vomiting and diarrhoea. Of note, a similar pattern was seen in up to 73% of cases of SARS in 2003, and 25% of cases of MERS. In these coronavirus infections, gastrointestinal symptoms occurred before subsequent manifestation of more severe respiratory symptoms. This indicates that pulmonary infection occurs after intestinal infection, and makes analysis of sewerage samples a powerful screening method to identify if there are cases occurring in specific communities.

The specific cell protein responsible for binding COVID-19, angiotensin converting enzyme 2 (ACE2), is found not only on cells in the lung, but also is expressed strongly throughout the gastrointestinal tract, particularly in the glandular cells of the gastric, duodenal and rectal epithelia and the enterocytes of the ileum and colon. Death of these enterocytes is the mechanism that explains enteric symptoms such as diarrhoea.

The presence of the virus in stools was identified in the very first case of COVID-19 infection in the United States. That patient had experienced nausea and vomiting for 2 days, followed by diarrhoea. The virus was present in the loose stools, as well as in respiratory and saliva samples. Intact infectious virus has been isolated from stool samples taken from patients with confirmed cases of COVID-19. Some patients showed virus in their stool even after their respiratory samples were negative. Some patients who have been hospitalised with COVID-19 and then have recovered and been discharged will continue to shed the virus in their stools, which could then drive further transmission within the community, if their faeces contaminates their hands and from there, contaminates surfaces they touch, or food they prepare, in the same way that norovirus spreads.

The recognition of COVID-19 infection in the GI tract stresses the importance of personal hygiene associated with the use of shared toilets. If an infected person forgets to properly wash their hands after using the toilet, then anything they touch afterward might be contaminated, including the toilet door handle. There needs to be a greater emphasis on maintaining and improving personal hygiene, not only in the workplace, but also for anyone who is preparing and serving food. Effective handwashing after using the toilet is critical, using liquid soap and water for at least 20 seconds and before eating or preparing food. Avoid touching the eyes, nose and mouth with unwashed hands.

In terms of environmental hygiene, it is prudent to use appropriate products to disinfect the surfaces of objects and surfaces that will be touched when using the toilet, including toilet control handles, support rails, taps and door handles or door knobs. All such “high-touch” surfaces that patients touch should be cleaned at least once every day. When using a wipe or spray, wear gloves and follow the label instructions to ensure safe and effective use of the product.

Yeo C, et al. Enteric involvement of coronaviruses: is faecal–oral transmission of SARS-CoV-2 possible? Lancet 2020 (February 19) https://doi.org/10.1016/S2468-1253(20)30048-0  and https://www.thelancet.com/journals/langas/article/PIIS2468-1253(20)30048-0/fulltext

Gu J, et al. COVID-19: Gastrointestinal manifestations and potential fecal-oral transmission. Journal of Gastroenterology 2020 March https://doi.org/10.1053/j.gastro.2020.02.054  and https://www.gastrojournal.org/article/S0016-5085(20)30281-X/fulltext

Xiao F, et al. Evidence for gastrointestinal infection of SARS-CoV-2. Gastroenterology. 2020; https://doi.org/10.1053/j.gastro.2020.02.055 and https://www.gastrojournal.org/article/S0016-5085(20)30282-1/fulltext

Holshue ML, et al. First Case of 2019 Novel Coronavirus in the United States. N Engl J Med. 2020 (January 31). https://doi.org/10.1056/NEJMoa2001191

Zhang H, et al. The digestive system is a potential route of 2019-nCov infection: a bioinformatics analysis based on single-cell transcriptomes. bioRxiv 927806 (January 30, 2020). https://doi.org/10.1101/2020.01.30.927806

Wang D, et al. Clinical Characteristics of 138 Hospitalized Patients with 2019 Novel Coronavirus-Infected Pneumonia in Wuhan, China. JAMA 2020 (February 7) https://doi.org/10.1001/jama.2020.1585

Date of Document: 18 September 2020

Receive more information