Researchers around the globe have been working tirelessly to develop a vaccine to treat the novel coronavirus which has caused devastation worldwide.

Earlier this month, Prime Minister Justin Trudeau said the “best minds” in Canada and abroad are working to develop treatments for the novel coronavirus, but that the country will not return to “the normal we had before” until a vaccine has been developed.

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Speaking at a press conference on Monday, Trudeau maintained that until a treatment is developed, Canada is going to “have to be very careful.”

Currently, there are more than 70 vaccine trials taking place around the world, including within Canada.

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Researchers say they are hopeful that a vaccine can be developed, but that it could be up to two years before it would be available for use.

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But what happens if researchers are unable to develop a vaccine, or if the virus mutates?

Here’s what experts say.

What happens if a vaccine is not developed?

Dr. Jeff Kwong, an infectious disease specialist who teaches at the University of Toronto, previously told Global News if a vaccine isn’t developed, a certain percentage of the population would need to become infected to develop what is known as ‘herd immunity’ in order for the pandemic to end.

The idea of herd immunity, Kwong said, is that enough people within a population are immune to a virus because they have already been infected, or they have been vaccinated that there is no one to spread the virus to.

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He said in this case, in without a vaccine, around half of Canada’s population would need to develop natural immunity virus.

1:50 Coronavirus vaccine reality check Coronavirus vaccine reality check

“So operating on the assumption that they do have protection after you’ve had the virus once, it’s probably going to be more than 50 per cent,” he said.

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But, Kwong said it is unclear at this time how long the immunity lasts, or even if those who have been infected would be protected at all.

“I’m not sure anyone knows,” he said. “I think especially because this is a new virus, we don’t know.”

The World Health Organization has expressed similar concerns, saying on Friday that there is currently “no evidence” to suggest people who have recovered from COVID-19 have antibodies that would protect them from a subsequent infection.

Without a vaccine, Canada is likely to see a number of “subsequent smaller humps” of the novel coronavirus over the next several years, Jason Tetro, a microbiologist and author of The Germ Code, told Global News.

“This is the first wave,” he explained. “And then the second wave is where you pick up all the people who didn’t get [it] the first time and so on and so on.”

David J. Kelvin, a professor at Dalhouse University’s Department of Microbiology and Immunology, also noted that antivirals may be useful in such a scenario.

“There are several groups working on antivirals,” he told Global News in an email. “I think if we fail at a vaccine, antivirals will become the main source of protection from disease by limiting viral infection or limiting viral growth once we are infected.”

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Is a vaccine the answer?

Tetro said to suggest things will return to normal after a vaccine is developed is a “lofty goal” to set because there is still “no proof” that it would provide full immunity against the virus.

He said the difficulty researchers encounter when developing a vaccine for coronaviruses is that the immune response is not always as strong as is seen with other viruses, including measles, mumps or influenza.

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That means a vaccine for this novel coronavirus may require either a number of booster shots, or several different vaccination steps over the course of a few years, Tetro explained.

“That is the big problem that we’re facing right now — how good is our immune system going to be after we get the vaccination?” he said. “So far, it hasn’t been that great.”

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Tetro added even if a vaccine is developed, the public should maintain some form of physical distancing and continue to practice proper hygiene.

“What I’m hoping is that even though the vaccine does look like it may be coming down the road, we don’t lose what we’ve already learned, because you never know when another one of these strains is going to come out of the wild and into the human population,” he said.

What if the virus mutates?

Asked if this virus could mutate, and if that would impact vaccine development, Tetro said that is “not going to happen,” because there “isn’t much mutation going on at all.”

“When you look at how many times this virus has gone through people over the course of the last four months now, you would have expected at least some kind of alteration that would change the way that it looks, the way that flu does,” he said. “We haven’t seen that.”

If that does happen, Kelvin explained scientists will have to create new vaccines each time it mutates.

“Several different strategies are being developed, many where the mutation site can be easily changed and the vaccine ramped up in a short period of time similar to sometimes of flu vaccines,” he said.

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Tetro added if another similar strain of this novel coronavirus emerges, and we have already developed a vaccine then we should have “partial immunity,” meaning we won’t end up with the same number of severe cases.

“If, however, we have something that is a completely different type of coronavirus but has the ability to cause severe infection, well, then once again, we’re back where we began, where we are essentially being exposed to a virus for the first time for which we have no partial immunity,” he said.