The head of Ontario's Science Advisory Table is urging people to stop their "wishful thinking" when it comes to the Omicron coronavirus variant, adding that any suggestion that the COVID-19 variant causes milder illness is a "myth."

"This is historical. This is unprecedented. This week Omicron will become the dominant variant in the province... People cannot imagine the sheer scale of what we are talking about here. It is really challenging," Dr. Peter Jüni, the head of the province's Science Advisory Table, said Monday morning.

"There is a myth out there that it's mild. We need to address this myth now."

Jüni said some believe that early data from South Africa indicates that the variant of concern causes milder illness but he was quick to point out some major differences between South Africa and Ontario.

"First of all, in South Africa, we only have about seven per cent of the population who are completely non-immune. All of those other people have either experienced infection, or vaccination, or both. We have about 30 per cent of the adults there who are immunological super humans because they actually were infected plus received two doses of the vaccine," he said.

"When you think about our situation, we have about 20 per cent of the population completely non-immune and we only have very few people, 10 per cent, who received their third dose or two doses and an infection. That's the difference we are talking about."

Jüni added that the median age in South Africa is about 27, compared to 44 in Ontario.

“Age is the most important risk factor,” he said. “So we need forget about wishful thinking here with mild disease. We simply don't know.”

According to the science table, the effective reproductive (RT) number for Omicron in Ontario is 3.32, meaning that every 100 new Omicron cases will go on to generate 332 secondary infections. All other previous variants of the virus combined have an RT value of 1.27.

The doubling time for Omicron in Ontario is now projected to be every three days, according to the Science Advisory Table.

"This variant here is so absolutely infectious now... This will reach every single person. Statistically speaking, there will be very few lucky ones," Jüni said.

"Once everybody has reached immunity, the game probably will change a bit. I would expect 2022, somewhere in spring, to change but first we need to get there and right now it grows very explosively."

Starting today, everyone aged 50 and older can book their third dose of a COVID-19 vaccine and the province has vowed to roll out booster shots to everyone 18 and older starting on Jan. 4.

But Jüni said the province currently has a "capacity problem" that needs to be fixed.

"We need to get to at least 200,000 doses per day and there will be a lot that will happen probably through the next few days and weeks," he said.

Over the past week, Ontario has administered no more than 80,000 vaccine doses on any given day.

"What we see from the UK now is against Omicron, after two doses, our protection against infection, not serious disease, but infection will start to wane after about 12 weeks. And this holds probably across all age groups."

In Ontario, it has been about five or six months since the majority of people received their second dose.

"This is a three-dose vaccine. Everybody needs to get vaccinated and we need to rush as fast as we can," Jüni said.