Gastrointestinal (GI) symptoms and COVID-19: more likely in severe disease

Electron micrograph of SARS-COV-2 virions in vitro

Some 12% of COVID-19 patients have gastrointestinal (GI) symptoms: 7% have diarrhea, and 5% have nausea and vomiting.  Fecal samples are positive for SARS-COV-2 in 41% of patients with positive nasopharyngeal antigen swabs.  Fecal shedding continues for several days after release from hospital.  Surveillance by samples taken from wastewater has revealed SARS-COV-2 antigen in municipal wastewater taken from many cities, often well before patients present with virus symptoms.

Testing by cell culture, however, reveals that antigen passed in stool is usually not infectious, probably because the virus has been disrupted by passage through the GI tract.  Only 2 of 153 patients had live virus on electron microscopy in their stool.  A significant number of patients had positive stool samples but negative respiratory samples.  One patient had a positive rectal swab 18 days after symptom onset.

Roughly 18% of patients had elevated liver enzymes, either alanine aminotransferase (ALT) or aspartine aminotransferase (AST).  The presence of GI symptoms and elevated liver enzymes appears to be associated with more severe infections.  In addition, some studies that tested environmental samples found virus at higher levels in bathrooms and on toilets.  All of the reported studies were observational and most came from China on or before March 20, 2020.

One obvious conclusion from this study is that infection control and prevention of nosocomial spread involves sanitation of toilet areas and frequent hand-washing for both patients and staff as well as civilians.

This information is taken from a meta-analysis of 23 peer-reviewed and six pre-print studies (out of 1484 altogether) on GI aspects of COVID-19 available on JAMA Network dated June 11 for free.