Fecal-Oral Route Does Not Appear to Be a Major Factor in COVID-19 Transmission
Klaus Mergener, MD, PhD, FASGE, reviewing Wölfel R. et al. Nature 2020 Apr 1.
While a significant number of patients with COVID-19 experience GI symptoms, and SARS-CoV-2 RNA can be detected in their stool, the risk of actual fecal-oral transmission of the disease remains unclear.
This study provides a detailed virological analysis of a cohort of 9 COVID-19 cases and their contacts to determine specific body-site replication and infectivity of the virus over several weeks. Pharyngeal shedding of the virus was very high during the first week of symptoms and then declined rapidly. The infectious virus was readily isolated from throat- and lung-derived samples. Blood and urine samples never yielded any virus. A high concentration of SARS-CoV-2 RNA was found in stool samples of infected individuals, but no infectious virus could be recovered from stool.
COMMENT
Diarrhea, nausea, vomiting, and abdominal pain are common in patients with COVID-19 and may sometimes precede respiratory symptoms. Multiple studies have found viral RNA in stool samples of patients with COVID-19, sometimes at very high levels. While this provides an indication that the virus may infect cells in the GI tract, it should not be confused with the presence of the infectious virus in stool nor the potential for fecal-oral transmission. The current study adds to the mounting evidence that the passage of infectious SARS-CoV-2 in stool is rare, if it occurs at all, and that fecal-oral transmission is therefore unlikely to be a major route for propagating the infection. Ultimate confirmation of this hypothesis will have to await larger-scale trials. In the meantime, GI endoscopists are well advised to err on the side of caution and wear appropriate personal protective equipment as recommended by the GI societies.
Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.
Klaus Mergener, MD, PhD, FASGE
CITATION(S)
Wölfel R, Corman VM, Guggemos W, et al. Virological assessment of hospitalized patients with COVID-19. Nature 2020 Apr 1. (Epub ahead of print) (https://doi.org/10.1038/s41586-020-2196-x)
American Society for Gastrointestinal Endoscopy, et al. Joint gastroenterology society message: COVID-19 use of personal protective equipment in GI endoscopy. Gastrointest Endosc 2020 Apr 2. (Epub ahead of print) (Joint message)
