COVID-19 cases and hospitalizations in Ontario will continue to rise substantially, even without the Omicron variant, if vaccination do not increase and further public health measures are not implemented, new modelling data released by the province’s science table suggests.

Experts with the Ontario’s Science Advisory Table released new modelling data on Tuesday to lay out all the possible scenarios the province is facing as the fourth wave continues to worsen and the mysterious new variant makes its way into the region.

“We can’t predict Omicron precisely, but it will almost certainly hit us hard and fast,” the scientists said in a series of messages on Twitter. “Cases are rising, even without much Omicron yet. Our hospitals and ICUs are feeling pressure again. We need to increase vaccination and we can’t let up on public health measures.”

Ontario has been struggling with a rapid increase in COVID-19 cases. The province’s seven-day average rose to 975 today, a level not seen since the decline of the third wave in early June. In addition, hospitalization have also been gradually increasing.

The scientists revealed on Tuesday that “even without Omicron” the number of people in the intensive care with COVID-19 is expected to climb to between 250 and 400 by January, putting hospitals under strain again.

Their projections showed, in the most likely scenario, which assumes 50 per cent of children would be vaccinated by the end of December, case counts rise well above 1,700 per day by mid-January.

In the worst-case scenario, if only 30 per cent of children between those ages are vaccinated and the public health measures continue as they are, case counts could go to nearly 3,000 per day. In this scenario, ICU cases also rise to nearly 400 by mid-January.

However, in the best-case scenario, experts say that if new health measures are implemented and 30 per cent of children get vaccinated before December ends, case counts will start to drop in mid January from 1,000 per day. ICU cases are also expected to start dropping in this scenario.

They scientists say that the spread of the Omicron variant will likely drive COVID-19 cases above the current projections.

 “The modelling is disconcerting … I am concerned about the coming months and its potential impact on our health care system and its potential impact on our healthcare system,” Ontario Chief Medical Officer of Health Dr. Kieran Moore said in a news conference on Tuesday. “The emergence of Omicron serves as a stark reminder of just how quickly things can change and how we must always keep our guard up.”

“As we enter the holiday season, I'm encouraging all Ontarians to avoid large crowds, practice physical distancing, wear your mask and wear it properly, wash your hands frequently, stay home when you're sick, and get vaccinated.” 

The modelling data warns of a rapid increase in daily cases in the province of Gauteng in South Africa, which indicates that Omicron is more transmissible than Delta. While the current situation is “very uncertain,” the scientists stated that the potential impact of Omicron on cases could be very substantial.

The modelling found that if Omicron proves to be “moderately” more infectious and if vaccines continue to be “moderately” effective against it, daily case counts will likely surpass 2,000 in January. If the new variant is “much more infectious” and “much more” resistant to vaccines, the scientists say that daily case counts could surpass 3,000 in January.

“South African data shows fast spread. But vaccines seem to protect against hospitalization, and this time we know how to stop transmission: masking, reducing contacts, ventilation. We’re not back to square one,” the scientists stated.

“We owe a huge debt to South Africa – whose public health system caught this, and whose scientists shared it immediately. Not the first time. Some countries really punch above their weight.”

The science table suggests that while vaccine effectiveness in Ontario remains very high, experience in other countries suggests a need to boost immunity with third doses.

The modelling data shows that people who are unvaccinated have a five-fold higher risk of symptomatic COVID-19 disease, a 13-fold higher risk of being in the hospital and 23-fold higher risk of being in the ICU compared to the fully vaccinated.

At least 13 cases of the Omicron variant have been detected so far in the province and the London, Ont. area health unit is investigating a potential cluster of 30.