Fecal-oral transmission of SARS-CoV-2: review of laboratory-confirmed virus in gastrointestinal system

Purpose: The objective was to collect the data available regarding the presence of laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in gastrointestinal system and to evaluate whether the digestive system could contribute to viral transmission. Methods: Bibliographic databases were searched to identify all studies documenting, in adult patients with a confirmed diagnosis of coronavirus disease 2019 (COVID-19): (1) the presence of SARS-CoV-2 ribonucleic acid in the feces; (2) the presence of SARS-CoV-2 ribonucleic acid in the intestinal cells; (3) live SARS-CoV-2 in the feces. Results: Twenty seven met the inclusion criteria. In 26 studies, the presence or absence of SARS-CoV-2 ribonucleic acid in the feces of COVID-19 patients had been reported. Out of the 671 patients, 312 (46.5%) had a positive stool sample for viral nucleic acid. Of these patients, 63.9% remained positive for viral nucleic acid in the feces after pharyngeal swabs became negative; Three studies also evaluated the viral ribonucleic acid in the gastrointestinal tissues and the presence of SARS-CoV-2 nucleic acid was found in samples of 3 patients out of 8 examined (37.5%). The presence of the live virus in stool samples was confirmed in two studies but no in in a recent study from Germany. These results suggested that SARS-CoV-2 could infect gastrointestinal epithelial cells and it may be transmitted through the digestive tract. Conclusion: In order to control the pandemic, every effort should be made to understand all the possible routes of transmission of the infections, even the less important ones.