By now, the most common symptoms of the novel coronavirus are engraved in the minds of people around the world.

Fever, cough, shortness of breath. Sometimes muscle pain, poor appetite and fatigue.

But as for which symptom comes first and when, it’s not as easily defined.

“There’s no playbook for progression,” said Dr. Isaac Bogoch, an infectious disease specialist based out of Toronto General Hospital.

“But that’s no different from other infections.”

Bogoch pointed to influenza as an example. He said that while the two illnesses are not equal, with influenza, some people start with a runny nose and others a sore throat. Some people “get really sick and die right away, while others just stay at home and get better,” he said.

Story continues below advertisement

“It’s so heterogeneous. It’s clear that there can be several different pathways.”

Part of the diversity in cases is tied to a person’s health prior to becoming infected, he said. Data so far suggests that the virus has affected older people with a history of chronic, pre-existing illness and that the chances of dying of the virus are higher for these people.

1:09Who to contact if you have COVID-19 symptoms


Who to contact if you have COVID-19 symptoms

A study of about 140 coronavirus patients at the Zhongnan Hospital of Wuhan University in China,