TORONTO -- Ontario's top doctor says thousands of unvaccinated students will face different isolation rules compared to their vaccinated peers in September.

Dr. Kieran Moore said the province's outbreak management plan for the new school year applies separate sets of rules based on vaccination status – and cautioned those who have yet to receive a vaccine they will be forced to learn from home if they're exposed to COVID-19.

Fully immunized students and staff would face minimal interruption from work or school if they come in contact with a "high-risk" carrier of the virus and test negative for COVID-19, Moore said.

"Terrific advantage of being two-dose immunized by being able to stay in school and attend sports and participate fully in all of the social activities of the school setting," Moore told reporters during his weekly COVID-19 update.

Unvaccinated students and staff, Moore said, would immediately have to isolate for a minimum of 10 days and require at least two negative COVID-19 tests, seven days apart, before returning to school.

"If that test on day seven is positive, you're off for another 10 days," Moore cautioned. "That is a potential of 20 days from schools directly because you weren’t immunized and because you’re infectious to others and putting others at risk."

The warning comes as the province struggles to convince more then 300,000 students eligible Ontario students to get their initial vaccine, despite accelerating the timeline between doses to 28 days after the first shot.

While the policy change had a dramatic impact on second doses, provincial data shows fewer residents in the 12-to-17 age range were signing up for a shot over the month of July, even as vaccine clinics started throwing open the doors for walk-in appointments.

Over the month of July, demand for a second dose among youth skyrocketed by 500 per cent. During the same period however demand for a first dose increased by just 13 per cent.

Now, with six weeks remaining until students are back in the classroom, provincial vaccine data shows 65 per cent of youth aged 12 to 17 have received one dose, while 42 per cent have been fully immunized.

Infectious disease specialist Dr. Isaac Bogoch told CP24 it's never been more convenient for the 333,000 eligible Ontario students who have yet to be vaccinate to get their shot.

"There's a ton of vaccines available, there's walk-in appointments, these are readily available just about everywhere in the province," Bogoch said.

"So if people are really wanting to be fully vaccinated before going back to school, now is the time to do it."

In order to be fully immunized before the start of the school year, families will have to pay close attention to the calendar.

For example, a student who received partial immunity on July 27, will be eligible for a second dose on Aug. 22, giving them the complete benefits of the COVID-19 vaccine just days before schools reopen.

NDP Education Critic Marit Stiles is calling on the Doug Ford government to "push, push, push" the vaccine ahead of the school reopening.

"The government has done very little to proactively push for that vaccination … they have not used all the tools at their disposal," Stiles said.