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A nurse guides people at a COVID-19 testing centre, in Toronto, on Dec. 10, 2020.CHRIS HELGREN/Reuters

Ontario has entered the third wave of COVID-19 as more transmissible virus variants account for almost half of new cases, the province’s science advisers warned Tuesday.

The Ontario COVID-19 Science Advisory Table said new data shows variants of concern are now driving pandemic growth, accounting for 733 of 1,489 total cases on March 15.

The group, which provides independent advice and analysis to the Progressive Conservative government, said that growth is taking place across the province.

“So, here we are: Ontario’s Third Wave,” the group posted to social media Tuesday. “Sadly, we are in fact ‘all in this together’. Ontario is organized into 34 public health units; almost two-thirds are now experiencing exponential growth of (COVID-19).”

The findings come a day after the province’s top doctor said that Ontario could be going into a third wave but the extent of it was still developing.

Which COVID-19 ‘variants of concern’ are in Canada? Alpha, Beta, Gamma, Delta and Lambda explained

COVID-19 is caused by a virus called SARS-CoV-2, and as it spread around the world, it mutated into new forms that are more quickly and easily transmitted through small water droplets in the air. Canadian health officials are most worried about variants that can slip past human immune systems because of a different shape in the spiky protein that latches onto our cells. The bigger fear is that future mutations could be vaccine-resistant, which would make it necessary to tweak existing drugs or develop a new “multivalent” vaccine that works against many types, which could take months or years.

Not all variants are considered equal threats: Only those proven to be more contagious or resistant to physical-distancing measures are considered by the World Health Organization to be “variants of concern.” Five of these been found in Canada so far. The WHO refers to them by a sequence of letters and numbers known as Pango nomenclature, but in May of 2021, it also assigned them Greek letters that experts felt would be easier to remember.

ALPHA (B.1.1.7)

  • Country of origin: Britain
  • Traits: Pfizer-BioNTech and Moderna vaccines are still mostly effective against it, studies suggest, but for full protection, the booster is essential: With only a first dose, the effectiveness is only about 66 per cent.
  • Spread in Canada: First detected in Ontario’s Durham Region in December. It is now Canada’s most common variant type. Every province has had at least one case; Ontario, Quebec and the western provinces have had thousands.

BETA (B.1.351)

  • Country of origin: South Africa
  • Traits: Some vaccines (including Pfizer’s and Oxford-AstraZeneca’s) appear to be less effective but researchers are still trying to learn more and make sure future versions of their drugs can be modified to fight it.
  • Spread in Canada: First case recorded in Mississauga in February. All but a few provinces have had at least one case, but nowhere near as many as B.1.1.7.


  • Country of origin: Brazil
  • Traits: Potentially able to reinfect people who’ve recovered from COVID-19.
  • Spread in Canada: B.C. has had hundreds of cases, the largest known concentration of P.1 outside Brazil. More outbreaks have been detected in Ontario and the Prairies.

DELTA (B.1.617 AND B.1.617.2)

  • Country of origin: India
  • Traits: Spreads more easily. Single-dosed people are less protected against it than those with both vaccine doses.
  • Spread in Canada: All but a few provinces have recorded cases, but B.C.’s total has been the largest so far.


  • Country of origin: Peru
  • Traits: Spreads more easily. Health officials had been monitoring it since last August, but the WHO only designated it a variant of concern in June of 2021.
  • Spread in Canada: A handful of travel-related cases were first detected in early July.

If I’m sick, how do I know whether I have a variant?

Health officials need to genetically sequence test samples to see whether it’s the regular virus or a variant, and not everyone’s sample will get screened. It’s safe to assume that, whatever the official variant tallies are in your province, the real numbers are higher. But for your purposes, it doesn’t matter whether you contract a variant or not: Act as though you’re highly contagious, and that you have been since before your symptoms appeared (remember, COVID-19 can be spread asymptomatically). Self-isolate for two weeks. If you have the COVID Alert app, use it to report your test result so others who may have been exposed to you will know to take precautions.

Need more answers? Email

“You can always tell you’re in it after it’s over,” Dr. David Williams said Monday. “I would say we are into that base of a third wave. What does that mean, how big it is, that’s to be determined.”

Premier Doug Ford said Tuesday that he will wait for Williams’ advice on the matter, but stressed people must continue to follow public health guidance even as more vaccines are administered.

“We can’t let our guard down for a second,” he said. “We have to be very, very cautious moving forward.”

Canada vaccine tracker: How many COVID-19 doses have been administered so far?

COVID-19 news: Updates and essential resources about the pandemic

Canada’s chief medical officer of health said Ontario has come to an “inflection point” in the pandemic after the province seemed to bring its second wave under control.

“What happens from this point on actually depends on the actions that are taken, as to whether this is a little bump or whether things might take off,” Dr. Theresa Tam said.

The Ontario Hospital Association said Monday that it believes province is now in a third wave, citing data from the science advisory group and saying the number of patients in intensive care is trending up.

The CEO of the Ontario Registered Nurses’ Association said the government lifted a stay-at-home order too soon, allowing the virus variants to spread.

Doris Grinspun said she fears the province will need to move back into lockdown.

“We need to be zeroing in 100 per cent on the vaccine now because this is our saving grace,” she said. “We are slow on the vaccines and we are quickly moving into the third wave. It’s a colliding disaster.”

Ontario Premier Doug Ford says people across the province can’t let their guard down as the province’s science advisers warn of a third wave of COVID-19. Ford said that people must continue to follow public-health guidance even as vaccines become more widely available.

The Canadian Press

The new data comes one day after the province launched a new COVID-19 vaccine online booking portal and call centre.

The province said Tuesday that 133,000 aged 80 and older booked their COVID-19 vaccine appointments Monday despite technical issues with the website and long wait times to get through to the call centre.

On Tuesday, an additional 21,000 appointments were booked by noon.

Toronto’s associate medical officer of health said cases in the city had been plateauing before the current upswing.

Dr. Vinita Dubey said defining the trend as a third wave depends on whether the increase is sustained.

“The variants are on the rise, that is for sure,” she said. “And if we see more cases, you can expect to see then the hospitalizations and deaths to be associated except where people are vaccinated.”

She pointed to the effective vaccination effort in long-term care homes and resulting drop in COVID-19 cases.

“Hopefully, as we approach another wave, we will have this protection around some of our most vulnerable to help prevent some of those severe outcomes,” she said.

Ontario reported 1,074 new cases of COVID-19 on Tuesday and 11 more deaths linked to the virus.

Another 51,579 doses of a COVID-19 vaccine were administered in Ontario since the last update.

Meanwhile, an all-boys private school in Toronto has temporarily moved all classes online after several students tested positive for COVID-19.

Upper Canada College says there have been 10 cases of the illness in students in grades 4, 8 and 12.

But it says there is no confirmation that the cases are a result of transmission within the school.

The school says holding remote learning until next week is a voluntary, precautionary measure to safeguard students, employees and the broader community.

With files from Holly McKenzie-Sutter.

Canada's top doctor Theresa Tam says there is a need to collect and analyze data on the new variants of the virus that causes COVID-19 to avoid new outbreaks. Tam says looking at the data coming from other countries is important but is not enough.

The Canadian Press

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