Toronto is adding hundreds of thousands of new appointments at its vaccination clinics over the next three weeks amid concerns about the spread of the Delta variant.

Mayor John Tory says that the 375,000 new appointments at city-run clinics will be available on the provincial booking site as of 8 a.m. tomorrow.

The appointments will be for the weeks of July 5, 12 and 19.

“You can see across Europe, including Britain, a slowing down of their reopening because of the Delta variant and they were running ahead of us as you know in some of those countries on vaccination. It is a real threat there in Europe and in Britain, such that it has caused their reopening timetable to be slowed down after it was announced, and we just don't want to see that happening here,” Tory said in making the announcement. “We want to fight it off here with our very best weapon, which is the vaccines.”

COVID-19 case counts have been steadily declining for months now in lockstep with rising vaccination rates.

But concerns have arisen about the potential for the Delta variant to eventually cause a surge in cases, given research suggesting that one dose of COVID-19 vaccine is less effective against the new, more infectious variant.

That in, turn, has led to a frantic effort to get more Ontarians second doses.

On Monday, the City of Toronto confirmed that more than a million residents have now been fully vaccinated, accounting for 41.8 per cent of adult residents. More than 76 per cent of adult Torontonians have received at least one dose.

“I think that you know we have to continue to draw to people's attention the experience that we've seen in other countries and that indeed the Delta variant has been a real factor in slowing down, for example, a much lauded reopening a schedule that was put in place by the British government,” Tory said. “So I think that beyond what is very intensive contact tracing and work that's being done on what is now a reduced number of cases, many of which are the Delta variant, I think the key is for people to get vaccinated because it provides that extra level of protection to them, especially for the second dose.”

The additional appointments being made available by the City of Toronto come as Ontario officially make all adults eligible to receive their second dose earlier than previously scheduled.

Tory said that while the vaccine rollout has mostly been a success to date there are still pockets of Toronto, particularly in city’s northwest corner, where vaccination levels “are under where we want them to be and need them to be.”

To that end, Tory said that he has asked staff about the possibility of staging another large-scale vaccination event like the one held at Scotiabank Arena this weekend in which more than 25,000 doses were administered.

“It is a huge logistical undertaking because we already have organized nine city-run clinics and we're doing I think 36 total clinics across the city today so your drawing resources off to do something special like that, but you're also achieving, you know, big results so it is something that is under advisement,” he said.

The Delta variant currently accounts for an estimated 69 per cent of Ontario’s new COVID-19 cases, according to the province’s science advisory table.