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.
“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.
A study of about 140 coronavirus patients at the Zhongnan Hospital of Wuhan University in China, located in the capital city once considered the outbreak’s epicentre, identified what could be a pattern of symptoms.
It’s a pattern observed in some of the most severe cases, ones that led to hospitalization, cautioned Alon Vaisman, an infection control physician at the University of Toronto. These types of cases are not as common, he said, but the data provides a possible timeline of the infection’s progression.
“Most people fighting the infection — around 80 per cent — won’t require admission to a hospital at all,” he said.
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“That 80 per cent is still a wide range of infection. It can be mild and it can be something more significant like fever, but still not necessarily bad enough to be brought into a hospital.”
According to the study, the symptoms, when broken down by days, look something like this:
Day 1: The first sign of symptoms appears, which can include fever, fatigue, dry cough, poor appetite, muscle pain and shortness of breath. While fever tends to be the most common, it may not necessarily be the one that develops first, Vaisman said.
Day 5: If people begin to develop difficulty breathing, it tends to happen around the fifth day from the time of infection, according to the study.
Day 7 or 8: “If you do start to develop respiratory failure, it’ll happen around the seven- or eight-day mark,” Vaisman said, citing the study. It’s around this time a patient will be admitted to a hospital.
“But the vast majority of people won’t get anywhere near that point,” he said. “Only about a quarter will develop this and require admission to a hospital.”
From then on, things can deteriorate further, but they can also improve.
“Some people will develop worsening respiratory symptoms, and this gets them admitted to an intensive care unit where they may require additional support for breathing, what we call getting intubated,” said Bogoch.
That, according to the study, tends to happen around Day 10.
In Canada, six per cent of cases have required hospitalization, as of March 26, with two per cent of cases requiring admission to the ICU.
Once in ICU, the progression of infection still isn’t linear, said Bogoch.
“People can take a turn towards a more severe course of illness with COVID-19 infection, but that can happen anywhere from right away to taking a week to two weeks to develop. And, of course, anything in between,” he said.
He added that it could take upwards of two weeks for someone to recover after getting to this point, and longer if they’re dependent on a ventilator in the ICU.
The first signs of symptoms also don’t tend to happen right away. A separate study, led by epidemiologists at Johns Hopkins University, found that the average incubation time of the new coronavirus is above five days.
“That means from the time you acquire the infection to when you first start having symptoms,” Vaisman explained.
There are other symptoms that are emerging as possibly related to the virus, including the loss of taste and smell, but Vaisman said it’s still not definitive nor is it known at what point it’s likely to develop — if found to be related to COVID-19.
“All we know are the most common symptoms — fever, fatigue, dry cough, poor appetite, muscle pain and shortness of breath. They’re the most important ones to watch out for, but they’re not going to occur in some sequence,” he said.
“It won’t be like this symptom first, that symptom second.”
While it’s also possible to be asymptomatic and be infected, Vaisman said the best people can do is keep an eye on how they’re feeling and self-isolate if they begin to notice changes.
“Keep track. Keep track of what symptoms you have and when they started,” he said. “You don’t need to keep a diary or a log, but be aware of these things, so if you do need to see a doctor, you know what to tell them.”
— with files from the Canadian Press
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