Every person with a cough and fever may be asking themselves whether they have COVID-19, but research has shown that gastrointestinal problems can also be a sign of novel coronavirus infection.
In a preprint study from March 18, scientists found that nearly 20 percent of 204 COVID-19 patients from hospitals in China’s Hubei province, where the outbreak began, had gastrointestinal issues like diarrhea, in addition to fever or respiratory symptoms.
Another analysis of COVID-19 patients in Wuhan, China, shows a distinct group of people with milder respiratory symptoms who experienced diarrhea, abdominal pain or nausea, says Brennan Spiegel, a gastroenterologist and director of Cedars-Sinai Health Services Research. Spiegel co-authored the analysis — also still in the preprint stage — showing about 20 percent of a patient group had diarrhea as their first symptom of infection.
And as we get further into the current pandemic, says Spiegel, we’re learning more about the 80 percent of people with COVID-19 who have milder symptoms, or are asymptomatic, and don’t need to be hospitalized.
“[They’re] out in the community right now struggling to figure out if the symptoms they’re experiencing could be [COVID-19], in particular digestive symptoms like diarrhea, nausea and vomiting,” he adds.
Those with mild gastrointestinal problems may not realize it’s a potential symptom of COVID-19 and take precautions to keep from spreading it. Researchers have found viral RNA in the stool of the COVID-19 patients, but it’s not yet known if, or when, that material is infectious.
It’s also difficult to determine what percentage of patients may show gastrointestinal symptoms, since they might not get themselves tested as readily as those with more serious respiratory symptoms.
Among those with respiratory symptoms, anywhere between 10 and 50 percent may also have digestive symptoms, “depending on the study,” says Spiegel.
But he also emphasizes that the disease is “almost as much a [gastrointestinal] illness as a respiratory illness.”
That’s because the cell receptors that the virus grabs onto are found in the gut in addition to the respiratory system. Those receptors — called angiotensin-converting enzyme-2, or ACE2 — are what the “spikes” associated with this coronavirus fuse onto in order to invade cells.
Testing stool might also provide a way to reduce false negatives of COVID-19 tests. In one study, the virus was detected in the stool of more than 50 percent of a particular group of COVID-19 patients. More than 20 percent of them had positive stool tests while having negative respiratory samples.
“[By] checking just respiratory without checking stool, you could miss cases,” says Spiegel.
People can “shed” the virus in their stool for up to five weeks, according to another study published in the journal Gastroenterology and Hepatology. Again, researchers are still trying to determine if — or for what period of time during the course of an infection — that stool would be infectious.
Another wrinkle is that it’s unknown how this virus will affect other disorders of the digestive system, including inflammatory bowel disease (IBD). These patients may experience a flare-up of disease symptoms, such as diarrhea or blood in their stool, if they develop COVID-19. In that case, they would have to grapple with a difficult question: How do they know if it’s the virus, or just their IBD acting up again?
University of Chicago gastroenterologist David Rubin says that other infections of the gut can cause relapses of inflammatory bowel disease, but they are still gathering data on how IBD patients react to the virus. For now, the International Organization for the Study of Inflammatory Bowel Disease has released guidance on how patients taking different immune-modulating prescription drugs should respond to the virus threat.
Everyone who has a loose stool here and there shouldn’t be worried, adds Rubin. The time to call the doctor is when respiratory symptoms or fever accompany that diarrhea.
But complicating matters is the fact that diarrhea can be a symptom of many things besides COVID-19 — even just stress, says Spiegel.
“Right now, people are under a great deal of duress and they’re having body symptoms and trying to figure out, ‘Are those symptoms from an infection or just in my head?’” says Spiegel. If a patient has new-onset diarrhea and fever, they need to call a doctor and self-quarantine, he adds.
Those sharing a bathroom should be careful to wipe it down with cleaner, use a different roll of toilet paper and even close the toilet seat so flushing doesn’t aerosolize particles of virus. The next step for researchers will be to confirm whether the virus can spread through stool — but, in the meantime, it’s fair to assume that it can.
“We’re learning very quickly that the [gastrointestinal] system is a center of action for this disease,” says Spiegel.