But this data has not yet been explored in COVID-19 patients.
Overall, 48 patients (23%) were admitted with digestive symptoms only, 89 (43%) with respiratory symptoms only and 69 (33%) with both respiratory and digestive symptoms.
The researchers were surprised to find that characteristics considered to be hallmarks of COVID-19, like certain patterns seen in lung images, fever, and strong immune responses, were not useful in predicting which of the many patients with initial, mild symptoms would go to develop severe lung disease. Instead, the new AI tool found that changes in three features - levels of the liver enzyme alanine aminotransferase (ALT), reported myalgia, and haemoglobin levels - were most accurately predictive of subsequent, severe disease.
The researchers emphasised that all of these patients had milder infections and recovered from the disease and that the study looked at a small number of patients. Their travel history may also shine a light on whether the patient has been in an area where COVID-19 is more prevalent.
On average, the patients still had the virus two-and-a-half days after no longer experiencing symptoms - but individual cases ranged up to eight days, the study said.
Spector's team applied their findings to the more than 400,000 people reporting symptoms via the app who had not yet had a COVID-19 test, and found that nearly 13% of them are likely to be infected.
"These data emphasises that patients with new-onset diarrhoea after a possible COVID-19 contact should be suspected for the illness, even in the absence of cough, shortness of breath, sore throat, or even fever".
"If you had mild respiratory symptoms from COVID-19 and were staying at home so as not to infect people, extend your quarantine for another two weeks after recovery to ensure that you don't infect other people", said co-author Dr. Lixin Xie of the Chinese PLA General Hospital in a statement.
"COVID-19 patients can be infectious even after their symptomatic recovery, so treat the asymptomatic/recently recovered patients as carefully as symptomatic patients".
The small European Union country, with a population of 11.4 million, now has 12,775 cases of persons tested positive for COVID-19, of whom 4,920 have been hospitalised, including 1,021 in intensive care.
Here are some of the less common symptoms of COVID-19 described by Science Alert published by BGNES. At least a couple of separate studies also showed that asymptomatic patients may be just as contagious as symptomatic ones. But that's not necessarily a bad thing.