Persistent viral shedding of SARS-CoV-2 in faeces - a rapid review

In addition to respiratory symptoms, COVID-19 can present with gastrointestinal complaints suggesting possible faeco-oral transmission. The primary aim of this review was to establish the incidence and timing of positive faecal samples for SARS-CoV-2 in patients with COVID-19.

A systematic literature review identified studies describing COVID-19 patients tested for faecal virus. Search terms for MEDLINE included 'clinical', 'faeces', 'gastrointestinal secretions', 'stool', 'COVID-19', 'SARS-CoV-2' and '2019-nCoV'. Additional searches were done in the American Journal of Gastroenterology, Gastroenterology, Gut, Lancet Gastroenterology and Hepatology, the World Health Organization Database, the Centre for Evidence-Based Medicine, New England Journal of Medicine, social media and the National Institute for Health and Care Excellence, bioRxiv and medRxiv preprints. Data were extracted concerning the type of test, number and timing of positive samples, incidence of positive faecal tests after negative nasopharyngeal swabs and evidence of viable faecal virus or faeco-oral transmission of the virus.

Twenty-six relevant articles were identified. Combining study results demonstrated that 53.9% of those tested for faecal RNA were positive. The duration of faecal viral shedding ranged from 1 to 33 days after a negative nasopharyngeal swab with one result remaining positive 47 days after onset of symptoms. There is insufficient evidence to suggest that COVID-19 is transmitted via faecally shed virus.

There is a high rate of positive polymerase chain reaction tests with persistence of SARS-CoV-2 in faecal samples of patients with COVID-19. Further research is needed to confirm if this virus is viable and the degree of transmission through the faeco-oral route. This may have important implications on isolation, recommended precautions and protective equipment for interventional procedures involving the gastrointestinal tract.