If the province wants to avoid a COVID-19 fourth wave and avert another lockdown, the Ontario government needs to send more vaccines to hot spots.

That's the message from doctors and local officials pushing for the Ford government to adopt a second dose strategy that focuses on hot spots to deter the growing threat of the Delta variant – B.1.617.2, which was first discovered in India and is known to be more than 50 per cent transmissible.

The Ontario COVID-19 Science Advisory Table estimates the Delta variant cases now make up 27 per cent of all new positive samples.

"B.1.1.7, we could not vaccinate our way out of that, but the Delta variant we can if we're strategic and if we listen to the science and work on the timeline of science, as opposed to the timeline of politics," said Dr. Michael Warner, the director of critical care at Michael Garron Hospital.

"If we want to move forward quickly and get back on our feet with respect to the economy, we need to go to where the COVID is."

Calls for a return to a hot spot strategy for second doses come after Dr. Lawrence Loh, Peel Region's medical officer of health, said the Delta variant would become the dominant strain in the region ahead of any other jurisdiction in Ontario.

It prompted the mayors of Peel to ask the Ford government to increase its allocation of vaccines to avoid the variant from spreading.

Ontario has vaccine momentum, Warner said, and if the government wants that to continue and sustainably reopen the economy, it should get residents in hot spots like Peel to be fully vaccinated.

"It's in everyone's best interest, no matter where you live in Ontario, to bring the hoses to where the fire is," he said.

Dr. Naheed Dosani, a palliative care physician at McMaster University Hospital, said Peel and other hot spots have been hit hard by COVID-19 as many essential workers live in those areas. In addition, many residents also live in multi-generational households.

Dosani warned that Peel will suffer again if the province does not change its vaccine strategy.

"We know the answers. We've been through this before. It worked when we shifted vaccines to hot spots through an equity-based approach," Dosani said.

"There's no excuse we should not be doing that now. We must do it properly and urgently."

He said a per capita approach is not enough to prevent a fourth wave.

Dr. Andrew Boozary, the executive director of social medicine at the University Health Network, agrees. He said the province needs to learn from the rollout of the first dose, and that means targeting hot spot neighbourhoods and providing them easy access to the vaccine.

"We saw that reallocation in line with the science. We saw that shift, and we saw neighbourhoods and hot spots who were at the bottom of the mix move right up and shoot up right to the top," Boozary said.

"But if we lose focus, if we take our eye off the health equity approach, and resort back to per capita, we are only deepening and widening the inequities. And this is something that I think so many have been calling for to see some real progress. And if we pull back, that progress is in real peril going into the summer."

On Thursday, in response to the mayors' request, Health Minister Christine Elliott said Peel is already receiving a large allocation of doses that would enable the region to focus on hot spot neighbourhoods.

Speaking to CP24 Friday night, Loh said the whole region of Peel is a hot spot that's why he is asking for additional allocations and eligibility to be expanded further.

He noted that studies have shown that one-dose coverage is not enough to protect someone from the Delta variant.

"So really, this ends one of two ways because it will end in the next few months. Either we managed to sidestep a fourth wave by getting second doses out more quickly in the region of Peel, or we have a fourth wave, which will also impact overall the province's efforts to reopen."

Loh shared that he had some 'promising' discussions with the province Friday.

"My hope is that we'll all come together because I think really the reality is, this is not about just protecting Peel. This is about protecting the entire province," he said.

Mississauga Mayor Bonnie Crombie said fully vaccinating residents of Peel will ensure that once the province reopens, it will remain like that.

"So, we're asking the province…not to play politics with vaccines but to do the right thing and to curb the spread of this new variant and prevent a fourth wave. What we do need are vaccines to the hot spots, and that means Peel," she said.

Brampton Mayor Patrick Brown said it will be to Ontario's peril if the provincial government does not take the threat of the variant seriously. He noted that many residents in his city work in crowded factories, where the variant could spread easily.

Brown said they need to be protected.

"We know the lessons from last time. Mistakes were made during the initial vaccine rollout where they did not focus on hotspots," he said.

"And my worry is that if they don't focus on the Delta variant in Peel and in Toronto, it will spread out across the province like it did last time. I don't want to see an unnecessary lockdown that can be avoided by strategic allocation of vaccines to where we know it'll spread."

While the province announced that it is opening second dose bookings to those over the age of 70 and anyone who had a shot by Apr. 18, Brown said the expansion of vaccine eligibility needs to be expedited as the average age of an essential worker is 36.

According to Peel Public Health, more than 70 per cent of adults in the region have received at least one dose of the vaccine.

Brown said Peel cannot afford a belated response from the provincial government.

"We can't afford indecision. The government can't dither on this," he said.

"We need vaccines to protect our essential workers and save Ontario from a fourth wave."