WATCH: Ontario top doctor says province will review what it means to be ‘fully vaccinated’ due to Omicron fears

"We're reviewing the definition of what will be fully eligible. We certainly are encouraging all those who are eligible ... for the third dose to get those," he said.

Moore said that more research would be done into the effectiveness of a third dose with the new Omicron variant of COVID-19, which according to the World Health Organization, presents mild symptoms.

"We'll be following the immune protection of a third dose against Omicron to understand what immunologically represents the best protection against Omicron, and that might change the definition of what is fully immunized," Moore said.

The announcement came during the Ontario government's announcements on Friday, where several updates were provided.

Moore said that he is "concerned" about the rise of cases in the province, saying 10 per cent of the samples detected at Public Health Ontario were positive for Omicron and "it's anticipated that we'll have a significant rise in the coming weeks and in the next month and that it may become a dominant strain very soon."

Provincial officials also announced that they would move forward with making digital or printed QR codes mandatory as a part of their proof-of-vaccination, and that those changes would come starting Jan. 4.

"With cases expected to increase during the winter months, and as we continue to monitor the evolving global evidence around the Omicron variant, we must remain vigilant. We are still learning about the new variant, but we can expect that the months ahead may be very challenging," Health Minister Christine Elliott said.