The city’s top doctor says Toronto residents need to do everything possible to “prevent history from repeating itself” when it comes to transmission of emerging COVID-19 variants.

At a news conference at city hall on Monday, Dr. Eileen de Villa, Toronto’s medical officer of health, said the B.1.617 variant, which was first detected in India, has the potential to cause explosive growth similar to the B.1.1.7 variant, which is now the dominant strain here in Ontario.

“Cases of the (B.1.617) variant have doubled in the UK in a little more than a week…. The government’s scientific advisors there believe it is a realistic possibility the variant is as much as 50 per cent more transmissible than B.1.1.7,” de Villa said.

“Early information suggests there may be some reduction in protection given by vaccines or naturally acquired immunity. But overall, it is still good news if you are vaccinated. It is something to think about if you are not.”

There are currently 36 COVID-19 cases in Toronto that are linked to B.1.617 but the province does not have a robust screening system set up for detecting those infections.

“I’m not predicting the emerging variants will do in Ontario what B.1.1.7 is still doing but I accept it is possible and we should do all we can to prevent history from repeating itself. The infectious new variants are here and we should act as individuals in that knowledge,” she said.

“As vaccinations increase, as we hear of opening up in other places, and as our weather improves, the temptation could be to get ahead of ourselves. At this point, I expect there will be more mixing of people in the coming weeks, especially given the warmer weather.”

She said in Toronto, there are still a significant number of people who have not yet received their first dose.

She added that while those who are partially vaccinated are at a decreased risk of infection and their “ability to come through an infection with mild illness is greatly enhanced,” they can still spread the virus to those who have no protection.

“When you consider the entire population of the city, which includes children under 12…. Just over 50 per cent of people have had a first dose. That is a considerable number of people still at risk and they need to continue to practice the steps for self-protection,” she said.

“COVID-19 is nimble and stories around the world tell us that it isn’t in full retreat. Every new infection is a new opportunity for COVID-19 to mutate. So it is the unvaccinated we need to think of in the next weeks and months.”

Make sure friends, family get vaccinated, de Villa says

She urged everyone who has received their first dose to play an active role in helping those they know get vaccinated.

“People listen to people they know. People gain confidence from the experiences they trust. So act to encourage the unvaccinated to change that. Act to help people get a booking. Act to help them get comfortable with vaccination if they are hesitant,” de Villa said.

“The more we drive the vaccination numbers higher, the better off we are sooner.”

She said while the easing of restrictions in the United States and the United Kingdom shows us what a new normal could look like, Ontario is not yet ready to lift public health measures.

A provincewide stay-at-home order is in effect in Ontario until at least June 2.

After weeks of declining case counts, hospitalizations and deaths, Britain marked a major milestone today, reopening indoor dining and other indoor spaces, including museums.

More than 100 million Americans are now fully vaccinated against COVID-19, prompting the Centers for Disease Control and Prevention to issue new guidance last week, telling those with both shots that masks are no longer required in most indoor spaces.

Ontario’s own vaccination campaign has picked up in recent weeks and the province has seen a steep drop in the number of new infections and hospitalizations each day but case counts still remain stubbornly high. On Monday, 2,170 new COVID-19 infections were reported in Ontario.

“We are not the United States or the United Kingdom yet,” de Villa said on Monday.

“We can be if we keep taking those protective measures to limit spread while we build up our vaccinated population and our body’s ability to prevail over the virus.”