TORONTO -- New modelling data released by Ontario health officials suggests that while COVID-19 cases are declining, the new highly-contagious U.K. variant poses a significant threat and will likely be the dominant strain of the disease in the province by March.

Officials released updated modelling on Thursday that suggested while testing for COVID-19 is down slightly, cases and positivity rates across the province are on the decline.

According to the government, hospitalizations have also decreased across Ontario but the number of patients in the province's strained intensive care units (ICU) has not fallen yet.

Health officials expect that ICU capacity will decrease to between 150 and 300 patients by the end of February.

The government has previously said that when there are more than 300 patients being treated for COVID-19 in the ICU it becomes nearly impossible to treat the needs of non-COVID-19 patients.

There are currently 358 patients in Ontario's ICU being treated for COVID-19.

According to the data, "modelling and international examples" suggest that despite the U.K variant of COVID-19 spreading in Ontario, if the province maintains public health interventions it should see a continued reduction in cases, even with a return to school.

"The new mutated SARS-CoV-2 are clearly spreading in the community and will likely be the dominant version of the virus by March," Dr. Adalsteinn Brown, co-chair of the province's COVID-19 science table, said on Thursday. "The new variants give us less room to relax and less room for error."

“The variant will be the dominant source of infection by March.”

The modelling data also found that Ontario's stay-at-home order, which came into effect on Jan. 12, has resulted in only a small reduction in overall mobility in the province.

According to the modelling, if cases fall at a daily rate of one per cent, Ontario would report about 1,700 new cases per day by the end of February.

If it were to drop three per cent, cases would drop under 1,000 per day by then.

Chief Medical Officer of Health Dr. David Williams has previously said Ontario would need to see less than 1,000 COVID-19 cases per day before lifting the lockdown.

Brown said that COVID-19 vaccines are likely still effective against the U.K. strain of the disease.

"I think it’s important to note that these are not the only variants that will emerge as the disease continues to spread."

Brown said it is "quite possible" that a future COVID-19 variant may not work with the current vaccines being distributed. 

COVID-19 cases are also declining across long-term care homes but deaths continue to rise, the province said. There have been 215 long-term care deaths associated with COVID-19 in the previous seven days.

According to the data, Ontario is likely surpass the total number of deaths from the first wave during the second wave.

Ontario surpassed 6,000 COVID-19 deaths on Thursday, with more than 1,400 of those deaths were logged since the beginning of January. 

When should Ontario lift the stay-at-home order?

Brown said that deciding on when to lift the stay-at-home order is a decision that still needs to be made by the government on a region-by-region basis, but added he worries about relaxing it – even if the case numbers are low.

"As the prevalence of the new variant of concern increases, it can really lead to a sort of almost kind of vertical-type takeoff in terms of numbers of cases, with doubling time really shrinking way down," Brown said. "I think I'd be urging that in any place where we have concern the cases may take off, you maintain the public health measures."

In terms of students returning to class, Brown said that in order for that to happen safely there needs to be "really strong surveillance of the disease across the province."

"Which means more testing in these places where we're worried that infections will spread … I think the testing is a critical issue."

According to the modelling data, sending students back to the classroom across the province would result in a slight increase in COVID-19 cases in Ontario.