Months after coronavirus was first detected, many questions remain unanswered

Click to play video: 'Coronavirus outbreak: Dr. Tam outlines public health strategy behind newly-approved COVID-19 antibody test'
Coronavirus outbreak: Dr. Tam outlines public health strategy behind newly-approved COVID-19 antibody test
WATCH: Canada's chief public health officer Dr. Theresa Tam outlines public health strategy behind the newly approved COVID-19 antibody test – May 13, 2020

More than four months after the first case of the novel coronavirus was detected in Canada, health officials and researchers are still working around the clock to better understand the virus and to develop treatments and vaccines to protect against it.

But while researchers have made some headway, several questions about the virus remain unanswered.

Finding the answers to these questions, experts say, is important as the country begins to reopen.

READ MORE: Wider testing, surveillance needed to catch asymptomatic COVID-19 cases, experts say

Asymptomatic spread and population immunity

Colin Furness, an infection control epidemiologist and assistant professor at the University of Toronto, said the biggest unanswered questions are what role asymptomatic people play in the virus’s transmission, and how many people in Canada have already been infected.

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“We don’t know what the background level is in the population, we don’t know how many people have it and we don’t know how transmissible it is,” he said. “We know people spread it asymtomatic but we don’t know how much.”

He said finding the answers to these questions is “hugely important,” and there are ways Canada could find answers.

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Coronavirus outbreak: Moderna vaccine candidate showing signs of success, will move to phase 2

The first, he explained, is to do what is called ‘sentinel testing.’

This means people who are at high risk of contracting the virus — such as grocery store employees or health-care workers — would be identified and tested repeatedly, Furness explained.

“And that would help stop the spread,” he said.

In a previous interview with Global News, Dr. Isaac Bogoch, an infectious disease specialist based out of Toronto General Hospital, said that as Canada reopens, officials should “completely lower the threshold” for diagnostic testing.

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“So even people with very mild symptoms should be informed that this could be COVID-19 and should have easy access to diagnostic testing,” he said.

READ MORE: As Canada eases coronavirus restrictions, testing must increase, experts say

Furness said Canada should also move forward with antibody testing. Just last week, Health Canada approved the sale of the first coronavirus serological antibody test.

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Dawn Bowdish, the Canada Research Chair in aging and immunity at McMaster University, previously told Global News that blood tests could help pinpoint asymptomatic cases or patients with infections mild enough to have never been tested.

Bowdish said the use of serological testing would be “the gold standard of understanding the spread of this infection,” and would help fill in the gaps surrounding Canada’s understanding of its epidemic.

READ MORE: Researchers ‘very confident’ vaccine for coronavirus will be developed

Furness said once the tests are available, health officials could randomly select a sample of the population and test them to see what proportion of the population has already developed antibodies.

But what level of protection those antibodies offer is another thing that remains unclear.

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With many other viruses, once someone has recovered, their body produces antibodies that help protect against a subsequent infection. But experts have said it’s unclear how long immunity lasts for this virus.

Under-reported symptoms

Click to play video: 'Coronavirus around the world: May 16, 2020'
Coronavirus around the world: May 16, 2020

According to Furness, another unknown is all the different ways the virus attacks the human body. Furness said if someone has COVID-19 but does not have the typical symptoms, they likely won’t be tested, and their infection could go undetected.

He said an example of this is that researchers now believe the virus may be linked to a series of strokes reported in young, otherwise healthy people.

“So say someone comes in and they’ve had a horrible stroke, they’re incapacitated and they die,” he said. “And we don’t notice because we’re not looking for (the virus).”

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READ MORE: Coronavirus — Some businesses begin to slowly reopen after long weekend

Furness said this is a problem we are not doing much to fix but is a “huge concern.”

That, to me, is a is a really problematic blind spot,” he said. “We know the virus kills people, but we only know if they’ve already been tested first.

Transmission dynamics

Another important question that needs to be answered is how, exactly, the virus is spreading.

Research suggests the virus is spread primarily through droplets — mainly through coughs or sneezes.

However, lab tests have shown the virus can also live from hours to a few days on some surfaces.

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Coronavirus: Ontario retailers get ready to reopen

What is still unclear, Furness said, is the percentage of people who are becoming infected by touching surfaces compared to those who have inhaled droplets.

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He said this is something that is very difficult to study but is important because it helps to inform our public health policy.

Where did the virus originate?

It is believed the outbreak started in a “wet market” in Wuhan, China where, like many markets in Asia, animals are bought and sold, often killed on-site to ensure freshness.

Experts say these wet markets are breeding grounds for new diseases because animals and people are in close contact, making it easier for zoonotic viruses to jump to humans.

READ MORE: Live updates — Coronavirus in Canada

Furness said it is important to know where the virus came from so we can prevent another outbreak from happening the same way.

“Once you know what the pathway was, then you can take steps to say, ‘OK, that animal can’t be at animal markets’ or whatever practice it is that brings that animal in contact with people,” he said. “We need to identify that it’s risky and we should stop doing that.

–With files from Global News’ Rachael D’Amore and David Lao

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