The German researchers found high levels of viral fragments in 13 stool samples from four patients in their study, but they were unable to grow virus from any of them. The paper noted, though, that all the patients had mild illness, and the fact that they could not find virus in their stool doesn’t rule out that it could happen in other cases.

“Further studies should therefore address whether SARS-CoV-2 shed in stool is rendered non-infectious though contact with the gut environment,” they wrote, adding that their findings suggest measures to try to stop spread of the virus should focus on respiratory tract transmission — protecting others from the coughs and sneezes of people infected with the virus.