Clinical characteristics and fecal–oral transmission potential of patients with COVID-19

Background A significant proportion of patients with COVID-19 generate negative pharyngeal swab viral nucleic acid test results but test positive using fecal samples. However, fecal–oral transmission of COVID-19 has not been established to date. The purpose of this study was to evaluate the duration of fecal swab positivity in COVID-19 patients after pharyngeal swab nucleic acid test turned negative and to explore its potential for fecal–oral transmission. Methods A retrospective analysis of clinical records, laboratory results, and chest computed tomography (CT) findings of 17 COVID-19 patients confirmed by laboratory tests from January 22 to February 7, 2020 at a tertiary hospital was performed. The potential of fecal–oral transmission was assessed by detecting the presence of SARS-CoV-2 nucleic acid in fecal swab samples. Results A total of 16 patients (94.1%) had fever; other symptoms included dry cough, dyspnea, nausea, diarrhea, sore throat, fatigue, and muscle pain. Three patients had decreased white blood cell counts, 7 had decreased lymphocyte numbers, and 7 had increased C-reactive protein levels. Fecal samples of 11 patients tested positive for SARS-CoV-2 nucleic acid, of whom the time for the fecal samples to become SARS-CoV-2 nucleic acid-negative was longer in 10 patients than that for pharyngeal swab samples, and only one case exhibited a shorter time for his fecal sample to become SARS-CoV-2 nucleic acid-negative compared to his pharyngeal swab sample. The remaining 6 patients were negative for SARS-CoV-2 nucleic acid in fecal samples. Conclusion In COVID-19 patients who tested positive for SARS-CoV-2 nucleic acid in both pharyngeal swab and fecal samples, the time for the fecal samples to become SARS-CoV-2 nucleic acid-negative was generally longer than that in pharyngeal swab samples. However, there is currently no evidence demonstrating that the virus can be transmitted through the fecal–oral route.