Researchers at the University of Southern California say they've found that the symptoms of COVID-19 tend to appear in a specific order, a discovery that could help enable earlier detection and treatment for numerous patients.
According to the study, published in the medical journal Frontier Public Health, the most likely order of symptoms is as follows: fever, then cough and muscle pain, followed by nausea and/or vomiting, and then diarrhea.
"Fever is number one, followed by cough, followed by aches and pains — and they do not all have to appear in sequence, they can appear together," Lahita said of the first grouping of symptoms. After that, he said, comes nausea and vomiting, followed by diarrhea.
Not all patients experience the same set of symptoms. But the new findings help underscore how COVID-19 differs from other well-known illnesses. While fever and cough are also associated with a number of other diseases, like the flu, the study notes that it was the timing in which these symptoms appear, and the later gastrointestinal symptoms, that set this virus apart.
In a press release about the study, USC scientist Peter Kuhn said that understanding the order of virus symptoms is useful during "overlapping cycles of illnesses" like the upcoming flu season.
"Doctors can determine what steps to take to care for the patient, and they may prevent the patient's condition from worsening," Kuhn said.
To discover the sequence, the USC researchers, led by doctoral candidate Joseph Larsen, examined medical records and other data on over 55,000 coronavirus cases in China collected over a nine-day span in February, along with a set of over 1,000 cases from December through January. They also compared their findings to data on 2,470 influenza cases in North America, Europe, and the Southern Hemisphere from 1994 to 1998.
"It is important to have this information," Lahita said. "Besides the things that we all talk about like loss of smell and loss of taste, again — fever, cough, muscle aches, nausea, vomiting, and then diarrhea are very good indicators of the fact that you may have COVID-19."