Potential faecal transmission of SARS-CoV-2
Potential faecal transmission of SARS-CoV-2. Jefferson T, Heneghan C.
Published on June 27, 2020
Transmission Dynamics of COVID-19
||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
||China, Singapore, USA
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.
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.
||Number positive/total number tested (%)
||Hubei, Shandong, and Beijing, China
||Viable virions in stool from 2 patients without diarrhoea
|Zhang J 2020
|Zhang W (2020)
||1st day of sampling: 4/16 (25)
5th day: 6/16 (38)
||Shanghai and Qingdao, China
||Day 3–13 after the onset 5/6 (83)
Day 18–30: 5/5 (100)
||Approx. 40% positive for viral RNA in faecal samples had diarrhoea
||Five were treated with antivirals, 4 developed GI symptoms
|The COVID-19 Investigation Team (2020)
||AZ, CA, IL, MA, WA, and WI, United States
||All 3 with diarrhoea were positive for viral RNA in stool
||Two with diarrhoea were negative for viral RNA in stool,
|Zhang Y (2020)
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.
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
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 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, epidemiologist.