Potential faecal transmission of SARS-CoV-2

Potential faecal transmission of SARS-CoV-2. Jefferson T, Heneghan C.


Published on June 27, 2020

Reference Amirian ES. Potential fecal transmission of SARS-CoV-2: Current evidence and implications for public health. Int J Infect Dis. 2020;95(1878-3511 (Electronic)):363-70. https://doi.org/10.1016/j.ijid.2020.04.057
Study type
Country China, Singapore, USA
Setting Various
Funding Details Non Reported
Transmission mode Oro-fecal

Bottom Line

SARs-CoV-2 may be transmitted oro-fecally, but the number of studies in the present study with findings of viable virions in the faeces is small making this mode of transmission uncertain.

Evidence Summary

The fourteen studies reviewed are very small, varying from 153 cases to a single case report. However, some of them report production of faeces containing a number of viable virions and the clearance time of these is longer than by the respiratory route.  Not all of the cases had gastrointestinal symptoms.

Study Geographic location Number positive/total number tested (%) Gastrointestinal symptoms
Wang (2020) Hubei, Shandong, and Beijing, China 44/153 (29) Viable virions in stool from 2 patients without diarrhoea
Zhang J 2020 Jinhua, China 5/14 (36) None 
Zhang W (2020) Wuhan, China 1st day of sampling: 4/16 (25)

5th day: 6/16 (38)

Cai  (2020) Shanghai and Qingdao, China Day 3–13 after the onset 5/6 (83)

Day 18–30: 5/5 (100)

Xiao (2020) Zhuhai, China 39/73 (53) Approx. 40% positive for viral RNA in faecal samples had diarrhoea
Tang (2020) Zhoushan, China 1/3 (33) None
Young  (2020) Singapore 4/8 (50) Five were treated with antivirals, 4 developed GI symptoms
The COVID-19 Investigation Team (2020) AZ, CA, IL, MA, WA, and WI, United States 7/10 (70) All 3 with diarrhoea were positive for viral RNA in stool
Ling  2020 Shanghai, China 54/66 (82) None
Chen  (2020) Guangzhou, China 11/28 (39) None
Chan (2020) Guangdong, China 0/7 (0) Two with diarrhoea were negative for viral RNA in stool,
Kam (2020) Kallang, Singapore 1/1 None


Zhang Y  (2020) Heilongjiang, China 1/1 
Wu (2020) Zhuhai, China 41/74 (55)

What did they do?

The study is a descriptive review of 14 studies looking at faecal excretion of COVID-19 to March 15 2020. The introduction also summarises what is known of faecal findings in SARS 2003.

It points out that especially the Amoy Gardens outbreak in Hong Kong was caused or accelerated by a possible oro-faecal spread from toilet aerosol. The study used a mixture of PCR and culture to test the virions isolated in the stools.

Study reliability

The review does not have a methods chapter and there is only one table describing the included studies. Given these characteristics and the small study size, the findings need updating and the evidence base needs developing.

Clearly defined setting Demographic characteristics described Follow-up length was sufficient Transmission outcomes assessed Main biases are taken into consideration
Unclear Yes Yes Yes Unclear *
* most studies are small and there are no methods chapter so that it is unclear how these studies were selected.

What else should I consider?

This is a single review of small studies. Further confirmatory studies need to be carried out. However, the possibility of oro-fecal transmission should not be discounted.

About the authors

Carl Heneghan

Carl is Professor of EBM & Director of CEBM at the University of Oxford. He is also a GP and tweets @carlheneghan. He has an active interest in discovering the truth behind health research findings

Tom Jefferson

Tom Jefferson, epidemiologist.