TORONTO -- Lockdowns have been initiated in the United Kingdom, as Canada as well as several European Union countries cancel flights after information was revealed about a new variant of the virus that causes COVID-19. Researchers are rigorously examining how the mutations arose, what it means for vaccines, and updating their understanding of the virus.

In a tweet, Prime Minister Justin Trudeau announced Sunday evening that Canada would be restricting flights from the U.K. for at least 72 hours. 

"This afternoon, I convened a meeting with the Incident Response Group. We focused on the new variant of COVID-19 identified in the UK, and we have decided to implement new border restrictions in order to keep you - and people right across the country - safe," the prime minister wrote on Twitter.

British Health Secretary Matt Hancock said Sunday the new variant, which had been announced by Public Health England last week, was now "out of control" but not more dangerous, adding that lockdown measures were being imposed to get it clamped down.

U.K. Prime Minister Boris Johnson told reporters this new variant is more than 70 per cent more transmissible. But he stressed, "There's no evidence to suggest it is more lethal or causes more severe illness."

"At the moment, it's really being flagged as one (variant) which is a very strong candidate for changing the transmission of the virus," Lucy van Dorp, senior research fellow in microbial genomics working at UCL Genetics Institute, told CTVNews.ca on Sunday.

Johnson explained the variant was likely the cause of an uptick of new cases in London and southern England.

Van Dorp explained that although preliminary evidence, such as from the European Centre for Disease Prevention and Control, points at its increased transmissibility, she's cautioning people to wait for more analysis and peer-reviewed studies.

On Sunday, the World Health Organization cautioned against major alarm, saying the fact that researchers detected the new variant means new tools to track the virus are working.

“(It’s) important to get across that this is a normal part of virus evolution,” WHO emergencies chief Mike Ryan told an online briefing. "Being able to track a virus this closely, this carefully, this scientifically in real time is a real positive development for global public health, and the countries doing this type of surveillance should be commended."

MUTATIONS ARE NORMAL FOR VIRUSES

WHO officials further explained that coronavirus mutations had so far been much slower than with influenza; and that when compared to other diseases, such as mumps, the U.K. variant was less transmissible.

For the past year, scientists have seen thousands of naturally-occurring mutations in samples of the novel coronavirus.

But none have led to worsening symptoms or affected how quickly the virus spreads -- until this latest mutation.

Infectious disease specialist Dr. Ian Brasg of Humber River Hospital told CTV News Channel on Sunday, "it's quite natural for virus to mutate and develop variants, many of which pose no greater risk than the original virus." But he added, "we really need to do our due diligence and find out what exactly is happening."

Van Dorp mentioned findings, on what’s been dubbed the "U.K. variant," are preliminary, with studies likely underway to better understand how much faster it allows the virus to spread, antibody responses and any effect it will have on COVID-19 vaccines.

FIRST POPPED UP IN SEPT.

A report released on Sunday by the COVID-19 Genomics UK consortium outlined how the strain, which goes by the name B.1.1.7, caught the attention of U.K. scientists earlier this month, because so many recently infected patients contracted this variant.

However, in a press conference on Saturday, chief U.K. science adviser Patrick Vallance explained that the variant had first been isolated on Sept. 20, and went on to account for approximately 26 per cent of cases by mid-November. But the number of cases skyrocketed in December.

“By the week commencing the ninth of December, these figures were much higher,” Vallance said. “So, in London, over 60 per cent of all the cases were the new variant.”

In the consortium’s report, “it has been speculated that it may have arisen from a chronically infected individual.” In other words, scientists hypothesize the high degree of mutations occurred during a long infection of a single patient.

This is because similar build-ups of mutations has been observed in “immunocompromised patients with chronic infections of SARS-COV-2,” according to the report.

WHAT MAKES IT MORE TRANSMISSIBLE?

Although data is fairly scant so far, this new virus variant involves mutations in the sequence that encodes its "spike" protein, according to Public Health England.

This protein is how the virus binds and infects cells, van Dorp explained. She said mutations to the protein’s genetic code are fairly important.

Van Dorp said the "high number" of mutations is being analyzed more because this protein is also what researchers have been targeting for vaccines and antibody-based therapies.

Previous studies have flagged mutations in this part of the sequence as "biologically relevant" she said.

"We also see that this variant is fairly unrelated to other viruses in circulation, so it seems to have adapted in some way that’s really worth following up on."

"I think it’s basically a yellow flag," Dr. Lynora Saxinger, an infectious disease specialist from the University of Alberta hospital, told CTV News Channel on Sunday.

"And it doesn’t seem to make it necessarily worse in terms of infection but it may make it worse in terms of transmission."

When it came to the uptick in new cases and this new variant, Saxinger said, "I think this serves to warn us about making sure that we suppress the virus spread as we’re waiting for the vaccine rollout."

WILL IT AFFECT VACCINES?

There was "no current evidence to suggest the new strain causes a higher mortality rate or that it affects vaccines and treatments although urgent work is underway to confirm this," the chief medical officer for England, Prof. Chris Whitty, said in a statement Saturday.

In its report, the COVID-19 Genomics UK consortium also stated, “At this point in time, there is no reason to believe that any of the mutations discussed here will affect vaccine efficacy.”

Johnson also said that there's no evidence that currently available vaccines will be less effective against it.

But Van Dorp said we need more evidence.

"But the expectation is that vaccines stimulate a broad antibody response. So they (the vaccines) are triggering a response to the entire spike protein, so if we have mutations in some regions (of the RNA), it doesn't seem like that would reduce the efficacy of the vaccine in a particularly significant way."

But she stressed changes to vaccine efficacy "wasn’t completely implausible."

COUNTRIES STOPPING FLIGHTS

Out of an abundance of caution, Canada and several European countries have cancelled flights from the U.K.

The Netherlands and Belgium have imposed a ban on flights. The Dutch government said the ban will last for at least the rest of the year, while Belgian officials issued a 24-hour flight ban and halted train links to the U.K.

France and Ireland will both impose a 48-hour ban on flights arriving from the U.K. Italy and Austria also joined the travel ban but the former didn’t specify how long the ban would last. Austria gave no immediate details on the timing of the ban, news agency APA reported.

In a tweet, Germany’s minister of health Jens Spahn, said the country is also set to restrict all travel to the U.K. and South Africa because of the new strain.

VARIANTS OF VIRUS COULD BE MORE WIDESPREAD

But despite these travel bans, faster-spreading versions of the virus could be far more widespread than is realized.

In South Africa, there’s another variant called as 501.V2, a lineage separate from the U.K. variant, that also has a mutation in the aforementioned “spike” protein. There, patients also appear to be affected by a faster-spreading version of the virus. Work from South African researchers was what first alerted their U.K. counterparts of the importance of this type of mutation in the “spike” protein.

And, according to a letter sent to the Netherlands’ parliament on Sunday, Dutch health minister Hugo de Jonge said they detected the B.1.1.7 variant specifically in sample from one patient taken in early December. Researchers there are currently trying to find out if there are other related cases and how the patient became infected.

Correction:

A previous version of this story incorrectly referred to a DNA sequence of the new variant of the SARS-CoV-2 virus. However, SARS-CoV-2 is an RNA virus. CTV News regrets the error.