Antivirals best defence against a disease that may be here to stay, says COVID-19 researcher

Even if an effective vaccine for COVID-19 is found, antiviral drugs could prove the best defence against a virus that may become a permanent threat, says a renowned Edmonton researcher.

'We hope we'll get a very effective vaccine but this is a disease that may well come back sporadically'

Dr. Lorne Tyrrell of the Li Ka Shing institute of Virology says Canadians should understand that good antiviral treatments could "change the course" of the disease, reducing its severity. (Travis McEwan/CBC)

Even if an effective vaccine for COVID-19 is found, antiviral drugs could prove the best defence against a virus that may become a permanent threat, says a renowned Edmonton researcher.

Dr. Lorne Tyrrell, the founding director of the University of Alberta's Li Ka Shing Institute of Virology, says despite the best efforts of researchers around the globe, the virus may become endemic. 

Even after the worst of the crisis has passed, outbreaks could continue, he said. 

"We hope we'll get a very effective vaccine, but this is a disease that may well come back sporadically," Tyrrell said in an interview Tuesday with CBC Radio's Edmonton AM.

"And once you have the disease, the vaccines are no longer effective. But antivirals can change the course of the virus." 

While the world focuses on flattening the curve and the race for a cure, Canadians need to understand that learning how to control the symptoms of COVID-19 is equally critical, Tyrrell said. 

Without a vaccine, it could take years for the population to build up sufficient levels of immunity. With a vaccine, it's unlikely that every person worldwide will be inoculated. 

Other previously novel diseases such as HIV and hepatitis C have never disappeared, but effective treatments have been developed to manage symptoms and spread, Tyrrell said. 

"Certainly, 'flattening the curve' is a phrase we all know now and how important that was," he said.

"I think, in individual cases, if you could find a way of changing the course of the disease with very effective antivirals, that would be a very important step as well." 

If COVID-19 is here to stay, antivirals could be a life line for infected patients and the medical professionals who care for them, Tyrrell said.

An effective antiviral treatment, when taken at the first sign of symptoms, could ensure most patients are spared from the extreme, life-threatening symptoms of COVID-19.

A race against time

Tyrrell said drugs currently used to manage shingles are a good example of the efficacy of antivirals. 

If you catch the symptoms of a shingles infection early and treat it within 72 hours of the rash appearing, patients will most likely avoid nerve damage that can cause pain months or even years after the blisters have gone away. 

Antivirals, however, become less effective the longer someone is sick, Tyrrell said. And so their use must be combined with effective testing and a fast diagnosis.

Achieving that will be a challenge, he said. COVID-19 is a rapidly moving disease which can put patients in intensive care in a matter of days, not weeks.

"If you wait, then the antivirals don't do much good," he said. 

"One day, I think, we will have such an accurate and quick diagnosis that we will be able to start treatment at that early time."

    With ongoing research there is reason to hope for an effective treatment, he said, and the Li Ka Shing Institute of Virology is equipped for the challenge. 

    Established in 2010, the organization focuses on the research of emerging viral diseases — with a focus on detection, diagnosis, prevention and treatment.

    The facility received samples of the virus earlier this year and began examining the genetic material in labs specially designed to protect researchers and the public from exposure to the deadly pathogens.

    Institute researchers, in conjunction with other labs at the University of Alberta, are directly involved with more than seven major research projects on the treatment and prevention of COVID-19.

    Two of the ongoing studies could result in an effective antiviral treatment, Tyrrell said.

    Remdesivir, a drug used in the emergency treatment of ebola patients, has shown promise as  a potential inhibitor for COVID-19. 

    The drug takes advantage of the coronavirus' natural life cycle. Masquerading as a part of the virus, the substance infiltrates the coronavirus genome, effectively shutting down its ability to make copies of itself. 

    Blocking replication could prevent damage and inflammation in the body, helping people to recover sooner.

    'A very effective drug'

    Tyrrell hopes the drug will continue to prove effective in ongoing clinical trials. 

    "Remdesivir is a very effective drug at inhibiting this virus and I'm sure we'll see in clinical trials the earlier we use it, the more effective it will be."

    Research led by biochemist Joanne Lemieux has also shown promise, he said. Lemieux and her team are working with an antiviral drug that has been successful in treating a cat coronavirus and is hoped to have the same effect on people with COVID-19.

    The drug relies on protease inhibitors. The compounds prevent the virus from spreading by damaging the enzymes that allow it to replicate inside a human host. 

    "That same protease inhibitor has gone through our testing for COVID-19 and we're hoping to see it go into clinical trials very soon," Tyrrell said.

    "It's very similar, almost identical in its structure, to a coronavirus that infects cats and causes a fatal disease in cats, but that disease can be turned around and changed quite dramatically with the use of the [protease] inhibitors." 

    Tyrrell, a member of the Canadian Medical Hall of Fame and of the Science Advisory Board to Health Canada, has been on the front lines in fighting some of the world's most insidious viral outbreaks. His research on viral hepatitis resulted in the first oral antiviral agent to treat chronic hepatitis B infection in 1998.

    Even after decades in the field, the scientific race against COVID-19 is unprecedented, he said. 

    "I have never seen such cooperation worldwide," he said. "There are outstanding examples of scientists coming together. Everyone is working hard to find a solution."


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