TORONTO -- The dates for when members of the general population can be vaccinated against COVID-19 in Ontario will be significantly accelerated if additional vaccine candidates are approved for use in Canada, a member of the province's vaccine distribution task force said on Thursday.

Dr. Isaac Bogoch, an infectious diseases specialist who sits on the province's 10-member vaccine distribution task force, told CP24 that the timelines presented on Wednesday are a "worst-case scenario."

Speaking at a news conference on Wednesday afternoon, Retired Gen. Rick Hillier, who is leading the province's program for vaccine distribution, said people ages 80 and over can begin to book appointments for vaccination starting on March 15.

Hillier added that the province expects to begin vaccinating those over the age of 75 starting on April 15 and people over 70 one month later. The target date for vaccinating people 65 and over is June 1, Hillier said, and July 1 for people 60 and over.

"Take those dates with a giant grain of salt. That would be like the worst-case scenario, the wheels have fallen off the bus," Bogoch said during an interview with CP24 on Thursday morning.

"That would be a very unlikely scenario to see it play out like that."

He said the timelines provided by the province on Wednesday do not account for the fact that more vaccines could be approved for use in the country, increasing Canada's supply of vaccines.

"It's challenging because people saw those dates and, rightfully so, we're very, very upset because if you are 60 years old, obviously you want that vaccine way earlier than July," he said.

"I think when you take a step back and you watch how this is going to be operationalized, we are going to see those dates bumped up significantly."

Canada expects to receive a total of four million vaccine doses from Pfizer-BioNTech and two million doses of Moderna's COVID-19 vaccine by the end of March. They are the only two vaccines that have been approved by Health Canada so far but other vaccine candidates, including AstraZeneca and Johnson & Johnson, are currently being reviewed.

Health Canada has indicated that it is in the final stages of the review process for AstraZeneca and if the vaccine is given the green light, nearly half a million doses could be shipped to the country next month as part of COVAX, a global vaccine-sharing program. In addition to agreements signed with Pfizer and Moderna, Canada has also inked deals to purchase millions of doses from both AstraZeneca and Johnson & Johnson when the vaccines are approved for use.

At Wednesday’s news conference, Hillier did not provide dates for when people under the age of 60 can expect to receive their first shot but the province has indicated that it intends to begin vaccinating younger members of the population in August.

Hillier also would not commit to the federal government's timeline of providing a vaccine to everyone who wants one by the end of September.

“I’d love to say by Labour Day weekend we are going to have every single person in Ontario who is eligible and who wants a vaccine to have one," Hillier said on Wednesday. "I’m a little bit reluctant to do that because it depends on the arrival of those vaccines."

With files from The Canadian Press