More than five per cent of positive COVID-19 cases collected last month in a major Ontario study tested positive for highly infectious coronavirus variants of concern, according to a new report.

Of the 1,880 positive samples from January 20 that were analyzed, 103, or 5.5 per cent were confirmed or highly likely to be either the UK B.1.1.7 or South African B.1.353 variants of concern.

Of those, 89 were from the Simcoe-Muskoka public health unit, with 85 of those directly linked to the Roberta Place long-term care home outbreak where 66 of 127 residents of the home have now died.

Other locations that generated variant cases on Jan. 20 were Peel (six cases), York Region (one case), Toronto (five cases), Waterloo (one case), and Durham (one case).

Public Health Ontario and other allied labs have run most positive COVID-19 cases from Jan. 20 through enhanced analysis including full genomic sequencing as part of a “point prevalence” study.

As of yesterday, there were 153 confirmed cases of the variants in the province, along with dozens of additional highly probable variant cases tied to outbreaks at long-term care homes in Simcoe County.

The B.1.1.7 variant, first discovered in England, is approximately 50 per cent more transmissible than older “wild” variants of coronavirus present in Ontario.

Scientists have said the B.1.353 variant, first discovered in South Africa, is also more infectious than older variants and may also circumvent some of the immunity given by some COVID-19 vaccines.

The head of Ontario's COVID-19 Science Table has said the B.1.1.7 variant will become the dominant strain detected among positive cases by March.

If the variants become dominant, existing public health measures will have to be prolonged or even enhanced in order to get spread under control, assuming mass immunity through vaccination is still months away.

That revelation has prompted the provincial and federal governments to introduce a series of new restrictions making air travel abroad more difficult.

Public Health Ontario said only 3 of the 103 variant cases detected from the Jan. 20 study were in people who had travelled abroad recently.

Variant cases are detected through a more detailed analysis of the results of standard PCR COVID-19 tests, coupled with more intensive and lengthy full genomic sequencing of the virus’ genetic profile.